(ABC NEWS) If some overseas passengers flying to the United States want to bring cell phones and other electronics onboard with them, they're going to have to show that the devices can turn on, the Transportation Security Administration said today. The move comes just days after the Department of Homeland Security announced TSA would be increasing security measures at certain airports overseas amid what ABC News learned was deepening concern that terrorists in war-ravaged Syria are trying to develop a new generation of bombs that could be smuggled onto commercial planes. "As the traveling public knows, all electronic devices are screened by security officers. During the security examination, officers may also ask that owners power up some devices, including cell phones," TSA said in a statement. "Powerless devices will not be permitted onboard the aircraft."