US Defense Secretary Ash Carter held talks on Monday with his Vietnamese counterpart Phung Quang Thanh on Monday the military cooperation between the two countries and the issue of South China Sea islands.

Carter discussed his call for an end to island-building in the South China Sea with Minister Thanh, who later told a news conference Vietnam had not been expanding its islands.

The two sides also signed a Joint Vision Statement to guide future military cooperation between the two former foes, who fought a 1955-1975 war and only normalized relations 20 years ago.

As part of the expanding cooperation, Carter announced the United States would help Vietnam establish a site to train its troops to participate in U.N. peacekeeping operations and would send a U.S. expert on peacekeeping to the U.S. Embassy in Hanoi.

On Sunday, Carter visited the Vietnamese navy headquarters and coast guard headquarters and pledged $18 million to help Vietnam buy U.S. patrol boats.

Carter, who is on his second visit to Asia since becoming defence secretary earlier this year, has been urging countries in the region to stop island-building efforts in disputed, resource-rich regions of the South China Sea.

He reiterated that call at the Shangri-La Dialogue security conference on Saturday, and discussed it with Thanh during their meetings on Monday.