Barack Obama, Li Keqiang, Najib Razak, Thongsing Thammavong

FILE - In this Nov. 22, 2015 file photo, U.S. President Barack Obama, left, shakes hands with Chinese Premier Li Keqiang, second left, while Malaysian Prime Minister Najib Razak, second right, and Laotian Prime Minister Thongsing Thammavong look on during the 10th East Asia Summit at the 27th ASEAN Summit in Kuala Lumpur, Malaysia. With the symbolic handshakes and unity photo-op, President Barack Obama's high-profile summit with Southeast Asian leaders in California this week aims to step up pressure against China's increasingly worrisome behavior in disputed waters. (AP Photo/Vincent Thian, File)