President Barack Obama declared on Oct. 29, 2010, that authorities had uncovered a "credible terrorist threat" against the United States following the overseas discovery of U.S.-bound packages containing explosives aboard cargo jets. The packages, which were intercepted in Dubai and the United Kingdom, originated in Yemen and were apparently bound for places of Jewish worship in Chicago, Mr. Obama said.

The package in England, discovered aboard a plane in East Midlands, north of London, contained a printer toner cartridge with wires and powder. It was found during routine screening of cargo in England, prompting authorities to scour three planes and a truck in the United States on Friday, U.S. officials said.

President Barack Obama declared on Oct. 29, 2010, that authorities had uncovered a "credible terrorist threat" against the United States following the overseas discovery of U.S.-bound packages containing explosives aboard cargo jets. The packages, which were intercepted in Dubai and the United Kingdom, originated in Yemen and were apparently bound for places of Jewish worship in Chicago, Mr. Obama said.

The package in England, discovered aboard a plane in East Midlands, north of London, contained a printer toner cartridge with wires and powder. It was found during routine screening of cargo in England, prompting authorities to scour three planes and a truck in the United States on Friday, U.S. officials said.

A jet lands near a United Parcel Service jet that is seen isolated on a runway at Philadelphia International Airport in Philadelphia, Friday, Oct. 29, 2010. Law enforcement officials are investigating reports of suspicious packages on cargo planes in Philadelphia and Newark, N.J.

Emergency response vehicles stand by as a UPS cargo plane after a suspicious package was found onboard on Oct. 29, 2010, at Philadelphia International Airport. Packages were found in Philadelphia and Newark, N.J. after federal investigators were alerted by the discovery of a potentially explosive device at an airport in East Midlands, England.

The tail section of a UPS plane parked at Liberty Airport Oct. 29, 2010, in New Jersey. Two suspicious packages intercepted on cargo planes in transit to the United States were addressed to religious institutions in Chicago, the FBI said Friday. Jewish synagogues were placed on alert and White House spokesman Robert Gibbs said that as a precaution, extra security measures were taken regarding other cargo planes at Newark and Philadelphia international airports.

Activity around UPS containers in the cargo area of East Midlands Airport, near Nottingham central England, late Friday Oct. 29, 2010. A suspicious package on a cargo flight at a British airport sparked a security alert in at least two United States cities.

President Barack Obama is briefed by members of his national security team in the Situation Room of the White House, Oct. 29, 2010.

Investigators are seen with a United Parcel Service jet near the company's facility at Philadelphia International Airport in Philadelphia, Friday, Oct. 29, 2010.

Police, fire, rescue and bomb squad personnel respond to the United Parcel Service staging area at Newark Liberty International Airport where a cargo plane was searched and a suspicious package removed on Friday, Oct. 29, 2010, in Newark, N.J.

UPS trucks drive by the scene where a cargo plane was searched for explosives after a suspicious package was found onboard on Oct. 29, 2010, at Philadelphia International Airport in Philadelphia.

President Barack Obama makes a statement to reporters about the suspicious packages found on U.S. bound planes, Friday, Oct. 29, 2010, in the James Brady Press Briefing Room of the White House in Washington.

A printer's ink cartridge containing white powder, confirmed to be PETN, intercepted in Dubai.

Printer cartridge with white powder intercepted in Dubai.

Part of printer intercepted in Dubai.

View of printer cartridge intercepted in Dubai containing PETN.

A computer printer whose ink contained explosive material. The device was prepared in a professional manner and equipped with an electrical circuit linked to a mobile telephone (SIM) card concealed in the printer.

View of printer cartridge containing PETN intercepted in Dubai.