ATHENS, Friday, Jan. 12 — A powerful explosion, reportedly caused by a rocket, rocked the American Embassy in Athens Friday morning.

Reuters, quoting the police and embassy officials, said that a rocket had been fired at the complex but that no one was hurt. The private-television station MEGA also reported that the cause was a rocket.

“This was a rocket attack launched from a building across the street,” a senior police official told Reuters. “It landed inside a toilet on the third floor of the embassy.”

Image An explosion at the U.S. embassy in Athens, reportedly caused by a rocket, was an act of terrorism, a police official said. Credit... Thanassis Stavrakis/Associated Press

Greek anti-terrorist officers were on the scene.

“This is an act of terrorism. We don’t know where from,” said the Attica police chief, Asimakis Golfis. “There was a shell that exploded in the toilets of the building.” He said it had been fired from street level.