As a huge international relief operation swung into action, aircraft carrier the USS George Washington and two cruisers arrived in Philippine waters on Thursday.
The carrier is expanding search-and-rescue operations and providing a platform for helicopters to move supplies.
The US military says its support will be on an unprecedented scale, with other US vessels due to arrive in about a week.
Pallets loaded with food and water have been taken from the aircraft carrier to Tacloban, the capital of badly hit Leyte province, and Guiuan.