The commander of the U.S. Navy Seventh Fleet called on Southeast Asian nations to form a combined maritime force to patrol areas of the South China Sea where territorial tensions flare with China.

Countries could streamline cooperation on maritime security while respecting sovereignty and coastal space, as in the case of counter-piracy efforts in the Gulf of Aden, Vice Admiral Robert Thomas said Tuesday at the Langkawi International Maritime and Aerospace Exhibition in Malaysia.

The U.S. has reassured allies in the region it will back them against China's assertions to about four-fifths of the sea. China has ratcheted up pressure on some Association of Southeast Asian Nations members, and has accelerated reclamation work on reefs in the waters crisscrossed by claims from Vietnam, Taiwan, Brunei, the Philippines and Malaysia.