MANILA - President Barack Obama landed in the Philippines Monday to cement new defence ties on the last leg of an Asian tour conducted against a backdrop of territorial tensions between US allies and China.
Obama flew into Manila from Malaysia, hours after the allies signed a new defence agreement allowing more US troops and defence hardware to rotate through the Philippines, part of a US rebalancing of military power towards rising Asia.
Obama was also preoccupied with the crisis in Ukraine, which has shadowed him around Asia for the last six days, as the United States and Europe gear up to slap new sanctions on Russia, likely within hours.
Obama was due to meet Philippine President Benigno Aquino, participate in a joint press conference and be honoured at a state dinner.
Anti-China sentiments run high in the Philippines, which is locked in a showdown with the Asian giant over disputed atolls in the South China Sea, part of a proliferation of maritime hotspots that has stoked Asian tensions.
During a tour that has taken him to Japan, South Korea and Malaysia, Obama has repeatedly warned that small nations should not be bullied by larger ones, a clear reference to China's increasingly sharp geopolitical elbows.
"Disputes need to be resolved peacefully, without intimidation or coercion, and... all nations must abide by international rules and international norms," Obama said in Malaysia Sunday.
Opening his trip, Obama made clear that US defence treaties with Japan did cover disputed islands long administered by Tokyo in the East China Sea, which are known as the Senkakus in Japan and Diaoyus in China.
The Philippines has its own territorial disputes with China in the South China Sea - notably over the Second Thomas Shoal, an outpost in the remote Spratly Islands.
US officials have not been so specific over their obligations towards Manila on territorial disputes - but it is clear they do not believe they are covered by the American Mutual Defence Treaty with the Philippines.
"With respect to some of the difficult territorial issues that are being worked through, it is hard to speculate on those because they involve hypothetical situations in the South China Sea," said deputy national security advisor Ben Rhodes.
"The US-Japan agreement has very specific coverage of territory under Japanese administration.
"Some of the disputes in the South China Sea raise more hypothetical circumstances." In essence, the difference lies in the fact that Japan already administers the Senkakus/Diaoyus while the status of other islands and reefs is disputed - even though they lie within the Philippines' internationally mandated exclusive economic zone and far closer to Filipino landmass than Chinese.
Brunei, Malaysia, and Vietnam, as well as Taiwan, also have overlapping claims to the sea, believed to contain vast deposits of natural gas and oil.