Ten sailors are missing and five were injured after a U.S. warship collided with an oil tanker east of Singapore on Monday.

The U.S. Navy said, the second accident involving U.S. Navy destroyers in Asian waters in little more than two months.

The guided-missile destroyer USS John S. McCain collided with the merchant vessel Alnic MC before dawn while heading to Singapore for a routine port call, the Navy said in a statement.

Reuters video footage from the Singapore Strait showed an area of impact about 6 meters (20 ft) wide in the John S. McCain’s port side, with crew members lining her decks. At 0600 GMT, the warship was seen moving towards Singapore’s Changi Naval Base under its own steam, accompanied by two vessels.

Four of the injured were evacuated by helicopter to a hospital in Singapore with non-life threatening injuries, while the fifth needed no further treatment, it said.