BOSTON -- A Massachusetts congressman who has long sounded alarms about terrorism and security procedures involving air and sea cargo is saying that the discovery of a suspicious device on a plane in the United Kingdom Friday is a "success story."

"This is the way that it should work. There has to be an international cooperative effort if we're going to thwart al-Qaida," U.S. Rep. Ed Markey said.

A suspicious package containing a toner cartridge with wires and powder was found during routine screening of cargo in the United Kingdom, prompting authorities to scour vehicles in the United States on Friday.

Planes in Philadelphia and Newark, N.J., were being swept, as was a truck in New York City. No suspicious cargo or devices have been found at Boston's Logan International Airport.

"I think the good news is that this plot ... was identified in Great Britain and while the story is still developing and we don't have all the facts, we should be very pleased the authorities in the U.K. and the U.S. found this," Markey said.

The White House issued a statement saying potential suspicious packages had been found on two planes in transit to the United States.

"Based on close cooperation among U.S. government agencies and with our foreign allies and partners, authorities were able to identify and examine two suspicious packages, one in London and one in Dubai. Both of these packages originated from Yemen. As a result of security precautions triggered by this threat, the additional measures were taken regarding the flights at Newark Liberty and Philadelphia International Airports," a White House statement said.

Markey said prevention should be the No. 1 goal in both countries.

"This underscores, once again, the importance of having 100 percent screening of air cargo," Markey said, adding that a goal of terrorists has been to place explosives into plane cargo bins. He said he believes the Department of Homeland Security can do an even better job of screening airplane cargo bins.