Police on Tuesday arrested a man carrying a crude explosive device near the heavily fortified U.S. Embassy in Cairo, Egypt's capital, according to security officials.

They said the man, whom they did not identify, was intercepted outside the concrete blast barriers that encircle the U.S. and nearby British embassies in the leafy district of Garden City.

The U.S. Embassy said in a tweet that it was "aware of a reported incident" near the embassy and advised American citizens to avoid the area.

The officials spoke on condition of anonymity because they were not authorized to speak to the media.

The area around the embassy has for decades been heavily policed, with concrete barriers blocking vehicular traffic in its immediate vicinity. The British Embassy is located across the road from the U.S. embassy building.