Philippine President Rodrigo Duterte plunged one of the United States' most important Asian alliances deeper into uncertainty on Wednesday by declaring upcoming U.S.-Philippine military exercises "the last", and ruling out any joint navy patrols.
The firebrand Duterte pledged to honor a longstanding security treaty with the United States but said China opposed joint marine drills in the Philippines starting next week and there would be no more war games with Washington after that.
"I am serving notice now to the Americans, this will be the last military exercise," Duterte said during a visit to Vietnam. "Jointly, Philippines-U.S.: the last one."
Duterte's remarks gave one of the strongest signs yet of fissures in a historic alliance that Washington has relied upon as it tries to cement its influence in Asia to counterbalance China's rapid rise. His foreign minister later said his comments had been taken out of context.
The Philippine military and U.S. Marines are due to hold annual amphibious landing exercises from Oct. 4 to 12 in the north of the Philippines main island Luzon. Military leaders from the two countries have also started preparing for a new set of exercises next year.
Duterte said he would establish "new alliances for trade and commerce" with Russia and China, but would maintain security agreements with Washington.
His near-daily outbursts against the United States began in earnest last month, when he spoke of alleged atrocities a century ago by the United States when it was the Philippines' colonial ruler.
Duterte then said he would order the pullout of the last remaining U.S. special forces stationed in the Philippines' restive south since 2002, who he said were complicating counter-insurgency operations.
Duterte told a gathering of the Filipino community in Hanoi there would be no chance of having naval patrols with Washington because it risked dragging the Philippines into a possible conflict with China.
He said any notion of conflict between the Philippines and China, which have long sparred over sovereignty in the South China Sea, were "not really anything, more imaginary".
The Philippines and the United States share concerns about China's military clout and pursuit of broad maritime claims, which overlap with those of Manila and other neighbors.
Asked repeatedly if Duterte was serious about ending military exercises with the United States, Foreign Secretary Perfecto Yasay said he was misunderstood and the remark taken out of context.
The only thing he ruled out was joint patrols beyond the Philippines' 12-nautical mile territorial waters, Yasay said.
"Our agreement, that will be respected and this is what the president clearly meant," he told a scrum of reporters, referring to a 1951 Mutual Defence Treaty.
But the latest comments add to uncertainty about what Duterte's end game is and whether Manila's next moves could complicate regional diplomacy or alter the status quo in the South China Sea.
Richard Jacobson, an American security expert, said Duterte's posturing could embolden China to exploit a testy relationship between two old allies.
"One could say that the U.S.-Philippines relationship might become strained and even shaken," Jacobson said.
"The U.S. geopolitical stakes in the region are much too high to react to his hyperbole. The current attitude in Washington is mature - more of patience than feeling provoked."
Duterte, 71, is hugely popular at home for his brash remarks and take-charge style. His volatility and frequent rants are a source of both amusement and concern, putting pressure on Philippine stocks and the peso currency.
He has not taken criticism of his deadly war on drugs well, calling both President Barack Obama and his ambassador to Manila a "son of a bitch" and referring to U.N. secretary Ban Ki-moon as a "devil".
The Philippines has not formally committed to joining the United States in patrols beyond its territorial waters in the South China Sea. It has carried out at least two patrols with the United States this year, in April and June, that remained within 12 nautical miles of the Philippine coast.
A U.S. defense official, speaking on the condition of anonymity, said he had not seen the Philippines make a formal request to stop sea patrols and the bar for something to be called a "joint patrol" with the Philippines was low.
"If the joint patrols stop, will this have any sort of major impact on the situation in the South China Sea? Most likely not," the official said.
(Additional reporting by Karen Lema and Manuel Mogato in MANILA and Idrees Ali in WASHINGTON; Editing by Alex Richardson)