Egyptian security forces detained a man on Tuesday after he threw an explosive device which detonated near the U.S. embassy in Cairo, three security sources said. The embassy is currently on lockdown, Breaking News Now tweeted.
Security officials say the device was spotted outside the concrete barriers that encircle the embassy and the ambassador's residence in the leafy district of Garden City.
The officials spoke on condition of anonymity because they were not authorized to speak to the media.
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 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.