WASHINGTON/LONDON: Security officials in Britain and Dubai intercepted parcel bombs being sent from Yemen to the United States in a “credible terrorist threat,” US President Barack Obama said Friday. He said the parcels were bound for “two places of Jewish worship in Chicago”. Suspicion fell on Al-Qaeda in the Arabian Peninsula, based in Yemen, which took responsibility for a failed plot to blow up a US passenger jet on Christmas Day in 2009. “Initial examinations of those packages have determined that they do apparently contain explosive material,” Obama told reporters in a televised briefing, calling it “a credible terrorist threat against our country”. The White House said earlier that “both of these packages originated from Yemen” and that Obama was notified of the threat Thursday night. One of the suspicious packages was found on a United Parcel Service cargo plane at East Midlands Airport, about 260 km north of London. The other was discovered at a FedEx Corp facility in Dubai. “As an additional safety measure, FedEx has embargoed all shipments originating from Yemen,” said Maury Lane, a spokesman for the world's largest cargo airline. “The package never was on a FedEx aircraft. We don't fly to Yemen.” British police said an item found on the UPS plane was sent for further testing. CNN said it was an ink toner cartridge converted into a bomb. Before Obama spoke, an FBI source had told Reuters that initial tests in Britain revealed no explosives. An official source in the United Arab Emirates said “an explosive device was found in the package that originated in Yemen” and that the parcel was similar to the one found in Britain. In the United States, UPS planes were checked in New Jersey and Philadelphia. The Transportation Security Administration said they were searched “out of an abundance of caution”. UPS, meanwhile, announced it was suspending all services out of Yemen until further notice, amid fears delivery firms were being used to launch a coordinated global terror attack. US officials and some analysts speculated that the suspicious parcels may have been a test of cargo screening procedures and the reaction of security officials. “One possibility, if this is terrorism related, is that this may be a trial run,” one US official said. Intelligence about the possible plot had come from an ally abroad, the official said, without elaborating. The US Department of Homeland Security said it was stepping up aviation security measures as a result of the scare. The British government said it was “too soon to say” whether it would follow suit but was “urgently considering” what steps to take about freight coming from Yemen. The Yemeni embassy in Washington said there were no direct flights from Yemen to Britain or the United States, adding that no UPS cargo flights land or take off from Yemeni airports. “As of now, we have no confirmation on the content of the suspicious package(s),” said Mohammed Albasha, an embassy spokesman. “The Yemeni government launched a full-scale investigation. We are working closely with international partners – including the US – on the incident.”