UPDATED 11/10/10 1:20 p.m.

LONDON (CBS) — A mail bomb intercepted last month at an English airport could have exploded over the East Coast of the United States, British police said Wednesday.

Forensic evidence showed the device, originally sent from Yemen by way of Cologne, Germany, was timed to be detonated about seven hours after the cargo aircraft carrying it left the U.K. for the U.S. The package was removed by police in Britain during transit.

“If the device had not been removed from the aircraft, the activation could have occurred over the eastern seaboard of the U.S.,” police said in a statement.

Authorities on both sides of the Atlantic said they only narrowly thwarted the plot, in which terrorists in Yemen hid two powerful bombs inside printers and shipped them to addresses in Chicago. One bomb was intercepted at central England’s East Midlands Airport and the other was discovered at a FedEx cargo facility in Dubai.

Officials at Flightaware, which tracks air traffic data, say that on the day of the attempted bombing the flight entered the U.S. through upstate New York.

They say it continued south through Pennsylvania and looped briefly into southern New Jersey while on approach into Philadelphia.

The Yemen-based al-Qaeda in the Arabian Peninsula has claimed responsibility for the bombs and has vowed to send more explosives-packed parcels.

In response to the near-attack, new rules have been put into effect banning air cargo shipments from Yemen and Somalia, two countries now identified as hotbeds of terrorist activity. Still, Schakowsky says that’s not enough. Also, passenger flights can now only carry printer toner and ink cartridges that weigh less than a pound.

The packages witht the bombs were both addressed to Chicago Jewish congregations. Authorities have not specified which ones, but sources told the Chicago Tribune they were on the city’s North Side. Following the discovery of the packages, police made increased checks in areas with a large number of synagogues, including the Edgewater, Rogers Park and West Rogers Park neighborhoods.

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