The U.S. Coast Guard said Saturday that it had verified all waterways as safe and reopened all major ports for boating in Guam after two Navy submarines became detached from their moorings due to a tsunami.

At about 8 p.m. on Friday the mooring lines holding the USS Houston and the USS City of Corpus Christi broke free from the pier at Naval Base Guam, U.S. Navy Joint Region Marianas officials said.

Tug boats from Naval Base Guam responded quickly to the situation and safely moored both submarines,” according to a released statement.

The USS Frank Cable and the USS Oklahoma City remained safely moored during the tsunami, the statement said.

Coast Guard Sector Guam said Saturday afternoon that damage assessments were being conducted inside Apra Harbor following the incident with the submarines.