Source: Explosives Found in Suspicious Packages Packed Powerful Punch

(CNN) -- Two suspicious packages found abroad that were bound for Jewish organizations in the United States contained a massive amount of explosive material that -- had the suspected terror plot not been thwarted -- would have triggered a powerful blast, a source close to the investigation said Friday.

U.S. officials believe that al Qaeda in the Arabian Peninsula, commonly referred to as AQAP, is behind the plot.

President Barack Obama confirmed that the packages -- intercepted in the United Kingdom and the United Arab Emirates -- originated in Yemen, the stronghold of al Qaeda in the Arabian Peninsula.

"We also know that al Qaeda in the Arabian Peninsula ... continues to plan attacks against our homeland, our citizens, and our friends and allies," he said during a press briefing on the incident.

One suspicious package, found at the UK's East Midlands Airport, contained a "manipulated" toner cartridge and had white powder on it as well as wires and a circuit board, a law enforcement source said. A similar package set to be shipped on a FedEx cargo plane was discovered in Dubai, the law enforcement source and Dubai officials said.

"Initial examination of those packages has determined they do apparently contain explosive material," Obama said.

The source close to the investigation said the type of material found in the devices was PETN, a highly explosive organic compound belonging to the same chemical family as nitroglycerin. Just six grams of PETN is enough to blow a hole in the fuselage of an aircraft.

PETN was allegedly one of the components of the bomb concealed by Umar Farouk AbdulMutallab, the Nigerian man accused of trying to set off an explosion aboard Northwest Airlines Flight 253 as it approached Detroit, Michigan, on December 25. AbdulMutallab is alleged to have been carrying 80 grams of PETN in that botched attack -- also believed to be the workings of al Qaeda in the Arabian Peninsula.

By comparison, the source said the two devices found Friday contained multiple times more PETN. The source also said it appears the devices were designed to be detonated by a cell phone with the help of a smaller amount of a second unidentified explosive substance.

The cell-phone theory was seconded by a wireless engineer for a major U.S.-based manufacturer, who analyzed a photo of one of the devices at CNN's request.

"This size and the shape of the PCB (printed circuit board) are typical to a handset cell phone type device," wrote Olivier Clerc, hardware application engineering manager for a cell-phone-parts manufacturer.

Both packages were bound for the United States, "specifically two places of Jewish worship in Chicago," Obama said.

The packages led to increased searches of cargo planes and trucks in several U.S. cities, said law enforcement sources with detailed knowledge of the investigation.

White House counterterrorism chief John Brennan said that "the materials that were found and the device that was discovered were intended to do harm."

Brennan said the discovery of the packages was made with help from Saudi Arabia, and issued a statement thanking the country for its "assistance in developing information that helped underscore the imminence of the threat emanating from Yemen."

A source with firsthand knowledge of the information told CNN that the Saudi Arabian government gave the United States tracking numbers of the two packages, allowing for quick tracing to the United Kingdom and Dubai.

Senate Intelligence Committee Chairwoman Dianne Feinstein, D-California, called the potential plot "a new novel thing -- and that is using FedEx and UPS planes to perhaps bring in something that might be explosive."

The Transportation Security Administration issued Friday afternoon a halt in the United States on all packages originating from Yemen, and shipping companies UPS, FedEx and DHL all said they were complying with the order.

Sen. Susan Collins, the ranking Republican on the Senate Homeland Security Committee, told CNN she is very concerned about holes in the system to screen cargo coming into the United States, said that had a credible intelligence source not warned about the suspicious packages, they may not have been detected with standard security procedures.

Collins, who was briefed by TSA chief John Pistole, said intelligence officials do not know yet if this was part of a larger plot, but she does believe al Qaeda is "continuing to test for vulnerabilities in our security system, and it appears we do have vulnerabilities in our system for transporting cargo."

After the packages were found Thursday night and Friday morning, authorities were tracking other packages shipped from Yemen in the same time frame, a law enforcement source said.

A Yemeni diplomat in Washington said that his government has opened a full-scale investigation into the incident but that it was too early to speculate or reach any conclusions.

Counterterrorism officials are taking the threat "very seriously," Obama said.

The Department of Homeland Security said it "had taken a number of steps to enhance security," including "heightened cargo screening and additional security at airports."

Some Jewish religious leaders in Chicago were alerted to the potential threat Friday, said Linda Haase, spokeswoman for the Jewish Federation of Metropolitan Chicago.

"We were notified about this earlier this morning," she said. "We are taking appropriate precautions, and we are advising local synagogues to do the same."

Rabbi Marvin Hier of the Simon Wiesenthal Center in Los Angeles, California, said that if synagogues were indeed the intended recipients of the packages, "this is just another indication of the dangerous world we live in where Jews are the principle target."

Meanwhile, U.S. authorities seemed most focused on inspecting cargo planes.

Investigators examined two UPS planes that landed at Philadelphia International Airport in Pennsylvania and another at Newark Liberty International Airport in New Jersey, said Mike Mangeot, a UPS spokesman. Authorities later gave the "all-clear" at both airports, the Transportation Security Administration said.

The TSA said authorities acted "out of an abundance of caution."

Yemeni Plane Crashes With About 150 Aboard

(CNN) -- A Yemeni airliner with 150 people aboard has crashed in the Indian Ocean off the island nation of Comoros, an aviation official in Yemen's capital said Tuesday.

The aircraft, from the national airline Yemenia, was en route to Comoros when it crashed about an hour from its destination, an airline official said. There was no immediate news of the fate of those on board.

The Airbus A310 was en route from Yemen's capital Sanaa to Moroni, the capital of Comoros, and most of the passengers were Comoran, an official at Sanaa's international airport said. Moroni is about 2,900 kilometers (1,800 miles) south of Yemen, off the east coast of Africa.

"We don't know if there are any survivors among the 150 people on the plane," Comoros Vice President Idi Nadhoim told Reuters.

Lawyer: Arkansas Shooter Tortured in Yemen

LITTLE ROCK (CNN) -- The Tennessee man suspected in Monday's attack on a recruitment center in Little Rock, Arkansas, was brainwashed and tortured while imprisoned in Yemen, his lawyer said Thursday.

"My client is a young man, I think, brainwashed," attorney Jim Hensley told CNN. "What else could be explained for a young man who's a true American, plays football, helps his grandmother and mows the lawns of his neighbors? Comes back and then finds himself in this situation? That is not a normal situation in my book."

Abdulhakim Muhammad, formerly known as Carlos Bledsoe, is charged with killing Pvt. William Long, 23, of Conway, Arkansas, and wounding Pvt. Quinton Ezeagwula, 18, of Jacksonville, Arkansas.

The 23-year-old convert to Islam has pleaded not guilty. But, according to court records, he told police that he had "political and religious" motives for the shooting.

In September 2007, Muhammad left Tennessee State University in Nashville, where he was studying business, and traveled to Yemen to teach English to children and to learn Arabic.

There, "he felt at peace with these people," even marrying a Yemeni, Hensley said.

But things began to change when his client was detained for a minor visa violation in Yemen and sent to prison, where he was housed with radical Islamic fundamentalists, Hensley said.

In November 2008, Muhammad was arrested in the port city of Aden for overstaying his visa and deported two months later in cooperation with the U.S. Embassy, a Yemeni official said.

There is disagreement about the time he was incarcerated. The lawyer said Muhammad told him he had served four months in prison.

Hensley said Muhammad told him that, during the last two weeks he was held, he was deprived of sleep and food and "was slapped around a little bit," enduring beatings on the backs of his legs.

During Muhammad's time in the prison, an FBI agent visited him not as an ally but as an interrogator, Hensley said.

However, Mohammed AlBasha, a spokesman for the Yemeni Embassy, rejected Hensley's assertion. "It is understood that the process of radicalization can take a number of years, not a couple of weeks," he said. "So, the statement that his lawyer made, that he was brainwashed and tortured for weeks in Yemen, are baseless."

The FBI agent "believed that Carlos was some kind of hardened terrorist hellbent on doing violence to America," Hensley said.

After he was released in January, Muhammad returned to Nashville, Tennessee, where his parents noticed their son was "fidgety, frustrated, can't sit still," Hensley said.

The same FBI agent approached him and threatened to put him under surveillance, "to do everything we can to cause you trouble," Hensley said.

A federal law enforcement source told CNN that the FBI was investigating Muhammad, but FBI spokesmen would not confirm any contact they might have had.

Hensley added that Muhammad's parents told him that, once he returned to Nashville, "he was a different human," one who blamed the United States for the war wounds suffered by some of the children whom he had taught, children without arms or legs.

He also blamed U.S. immigration policy for his inability to bring his bride back to the United States with him, Hensley said.

"A first-year psychology student would be able to see that this young man needed some help, and that wasn't offered him by anyone," Hensley said.

Muhammad eventually moved to Little Rock to help his father's Memphis tour business expand into Arkansas.

Just before the shooting, he was working out of a Hilton hotel in Little Rock in the family business, driving a sightseeing van.

Hensley said he was speaking to the news media because Muhammad had asked him to. "His agenda is different from mine; he wants to be a martyr," the lawyer said.

The case has attracted high-level attention, with President Obama saying Thursday in a written statement that he was "deeply saddened" by the shootings.

Federal agents said Wednesday that they were looking into whether Internet searches of various locations in several other U.S. cities were a sign that Muhammad was seeking "additional targets." The cities investigators included Atlanta, Georgia; Louisville, Kentucky; New York; Philadelphia, Pennsylvania; and Memphis, Tennessee, where Muhammad grew up.

Hensley told CNN that his client was not the only person who was using the computer.

Muhammad is being held on a state count of capital murder and 16 counts of engaging in a terrorist act by firing into an occupied building.