Obama pledged to take a strong role in regional affairs, something welcomed by leaders in the fast-growing region.
The meeting between Obama and the 10-member Association of Southeast Asian Nations comes as China, the other superpower in the region, and its neighbors bicker over territorial claims in surrounding seas.
According to a readout of the meeting provided by the White House, the leaders "agreed on the importance of peaceful resolution of disputes, freedom of navigation, regional stability and respect for international law, including in the South China Sea."
China also has differences with Japan in the East China Sea, although tensions between the neighbors were eased after Japan released a Chinese fishing boat captain involved in a collision near disputed islands. Japanese Prime Minister Naoto Kan called Friday for calm in ties between the countries.
Southeast Asian leaders have welcomed Washington's presence in the region.
Vietnamese President Nguyen Minh Triet said ahead of the leaders' meeting that US-ASEAN ties are crucial "to the security, peace and development in the region." Obama spoke of strengthening ties and of "unprecedented cooperation between ASEAN and the United States."
"As a Pacific nation, the United States has an enormous stake in the people and the future of Asia," Obama said.
"We need partnerships with Asian nations to meet the challenges of growing our economy, preventing proliferation and addressing climate change." "The United States intends to play a leadership role in Asia," Obama said.
That could cause friction with China, the region's traditional heavyweight.
Beijing was furious after US Secretary of State Hillary Clinton told a regional security forum in Vietnam in July that the peaceful resolution of disputes over the Spratly and Paracel island groups was an American national interest. Beijing said Washington was interfering in an Asian regional issue.
The United States worries the disputes could hurt access to one of the world's busiest commercial sea lanes.
China claims all the South China Sea, but Vietnam, Taiwan, Malaysia, Brunei and the Philippines have also laid territorial claims. Aside from rich fishing areas, the region is believed to have huge oil and natural gas deposits. The contested islands straddle busy sea lanes that are a crucial conduit for oil and other resources fueling China's fast-expanding economy.
On Thursday, the president of the Philippines, Benigno Aquino III, welcomed a strong US role in the region. He said ASEAN would be unified should China use its weight as regional superpower in territorial disputes.
In a reference to China, Aquino said: "Hopefully we don't hear the phrase 'South China Sea' with reference to it being their sea." Obama also spoke Friday of growing US-ASEAN trade.
"The region is home to some of our largest trading partners and buys many of our exports, supporting millions of American jobs," Obama said. "American exports to ASEAN countries are growing twice as fast as they are to other regions, so Southeast Asia will be important to reaching my goal of doubling American exports."
