The US Government has increased the screening of incoming air cargo following the interception of two packages of explosive devices that originated in Yemen.
The packages found on a FedEx cargo plane contained chemical explosives camouflaged as printer cartridges and wired to be detonated by a cell phone.
US representative Michael McCaul, a Homeland Security committee member, said the bombs exposed a weakness in the way cargo is screened on its way to the US.
The first package, originating in a United Parcel Service shipment from Yemen, was discovered at a cargo distribution centre at East Midlands Airport in the UK.
Another package was found on an Emirates commercial passenger jet carrying cargo from Yemen, according to The Los Angeles Times.
In another incident, a small bomb was found inside a car at Belfast International Airport in Northern Ireland.
The 40kg bomb was examined by police and army bomb experts and was later defused.