President Barack Obama and the leaders of Southeast Asia called Tuesday for peaceful resolution of the region's maritime disputes as they concluded a summit in California.
Obama told a news conference that disputes must be resolved by legal means, including a case brought by the Philippines challenging China's sweeping claims over most of the South China Sea.
China has refused to take part in the proceedings, but Obama said parties to the U.N. law of the seas are obligated to respect the ruling, expected later this year.
Obama has been hosting 10 leaders of the Association of Southeast Asian Nations, or ASEAN, in the U.S. for the first time. That sends a subtle message to China that the U.S. remains an important force in the region.
But the leaders' joint statement after two days of talks avoided direct reference to China, reflecting the careful path that ASEAN members tread in their diplomacy with the world powers.
"Any disputes between claimants must be resolved peacefully through legal means such as the upcoming arbitration ruling under the U.N. Convention of the Law of the Seas, which the parties are obligated to respect and abide by," Obama said.
The Philippines brought its case in 2013 after Beijing refused to withdraw its ships from a disputed shoal under a U.S.-brokered deal. Despite China's refusal to participate, the arbitral tribunal based in The Hague has agreed to hear the case.
China says it has a historical right to virtually all of the South China Sea and has built seven artificial islands, some with airstrips, to assert its sovereignty. Taiwan and ASEAN members Brunei, Malaysia, Vietnam and the Philippines also claim land features in these potentially resource-rich waters, an important thoroughfare for international shipping.
Though not a claimant, the U.S. has spoken out against China's conduct and has angered Beijing by sailing U.S. Navy ships near some of the artificial islands to demonstrate freedom to sail there despite China's territorial claims.
Obama said the U.S. will continue to fly, sail and operate wherever international law allows, and it will support the right of other countries to do the same.
The U.S. has long argued for the maritime rights issue to be resolved peacefully and is looking for ASEAN to take a unified stance on the issue.
The diverse group of countries includes governments that lean toward either Washington or Beijing. Only four ASEAN members are South China Sea claimants, leading to sometimes conflicting views on how to handle long-simmering rifts.
The U.S.-ASEAN joint statement did not refer directly to the arbitration case brought by the Philippines, but it does urge "full respect for legal and diplomatic processes" in resolving disputes.
Singapore Prime Minister Lee Hsien Loong told a working dinner of the leaders on Monday night that China's role in the region is expected to grow. Loong said China's larger presence will likely lead to occasional frictions, uncertainties and anxieties, including on the South China Sea, but these issues must be managed peacefully to preserve regional stability and security, the Singapore-based Channel News Asia reported.
The summit is the latest effort by Obama to deepen U.S. ties with the fast-growing economies of Southeast Asia — a commitment he described as "strong and enduring." Obama plans to visit Vietnam in May, and then in the fall, become the first U.S. president to visit Laos.
Human rights activists have criticized Obama for hosting Southeast Asian leaders who have not come to power in free and fair elections. Obama said the U.S. would continue to stand with those in the region looking to advance rule of law and good governance.
He encouraged the return of civilian rule in Thailand, a long-standing U.S. ally, whose current prime came to power in a May 2014 military coup.
The leaders concluded the summit by posing for the traditional family photo on the plush lawn outside a historic residence at Sunnylands, the storied California desert estate where the talks were held. Sunnylands is also where Obama had his first formal meeting with China's current president, Xi Jinping, in 2013.
The leaders also discussed economic cooperation. ASEAN members Brunei, Malaysia, Singapore and Vietnam are all members of the Trans-Pacific Partnership, a free trade pact that is the main plank of Obama's outreach to Asia.
This story has been updated.