If you’re flying into the US from certain countries, you may discover that getting through security will become even more time-consuming and stressful. The US Transport Security Administration revealed on Sunday that enhanced security procedures on flights coming to the US now include not allowing uncharged cell phones and other devices onto planes. In a statement earlier this week, Homeland Security Secretary Jeh Johnson said that the new measures were the result of a re-evaluation of measures “to promote aviation security.” There is no official list of which airports are affected. However, the BBC is reporting that London’s Heathrow is one of them. Reports suggest that the enhanced measures are in response to information that terrorists in Syria and Yemen have developed bombs that might evade the previous screening processes.