An American Airlines' crew member was found to have 30 live bullets in his carry-on baggage last weekend at Narita International Airport, near Tokyo, during boarding procedures for the United States, investigators said Wednesday.

The bullets were found Saturday at the airport's security check point for flight crew, where the U.S. national in his 50s told police that he had forgotten the bullets were in his bag when he left the United States.

The police are considering charging him with violation of the swords and firearms control law. But they did not detain the crew member, and allowed him to leave Japan on a Dallas-bound flight Saturday afternoon after he promised to return to Japan if summoned. The U.S. airline company also showed willingness to cooperate with the probe, the investigators said.