The US has said it will seek clarity on the Philippine president’s announcement of a “separation from the US”.
Rodrigo Duterte made the comments in China on Thursday at an economic forum, saying the separation applied to military and economic co-operation.
US officials said the remarks were “at odds” with the “close relationship” shared by the countries.
Mr Duterte has grown increasingly hostile towards the US – a traditional ally – since taking office in June.
His presidential spokesman said the latest comments were a “restatement” of “independent foreign policy”.
“This is not an intent to renege on our treaties, but an assertion that we are an independent and sovereign nation,” Ernesto Abella said on Friday.
He explained Mr Duturte wanted to “separate the nation from dependence on the US and the West and rebalance economic and military relations with Asian neighbours”.
On Monday, the Philippine Secretary of Trade and Ministry Ramon Lopez told the BBC that the Philippines would not be stopping trade and investments with the US.
“We are still maintaining a relationship with the West, but we are reducing or doing away with too much dependence,” said Mr Lopez, who is in Beijing as part of Mr Duterte’s visit.
Mr Duterte also recently said he would end joint military exercises with the US.
And he has admonished the US for criticising him over his bloody war against drugs that has been linked with thousands of extrajudicial killings, and said US President Barack Obama could “go to hell”.
‘Three of us against the world’
On Thursday he told people attending the business forum: “I announce my separation from the United States. Both in military, not maybe social, but economics also. America has lost.”
“I’ve realigned myself in your ideological flow and maybe I will also go to Russia to talk to [President Vladimir] Putin and tell him that there are three of us against the world – China, Philippines, and Russia. It’s the only way,” Mr Duterte said.
This was not the Philippine president’s first mention of a separation from the US.
US State Department spokesman John Kirby said the US was “baffled by this rhetoric” and that Assistant Secretary of State Daniel Russel would be in Manila this weekend and would try to get some answers.
“We are going to be seeking an explanation of exactly what the president meant when he talked about separation from the US,” Mr Kirby told reporters.
Mr Duterte is in China with a large entourage of businessmen and diplomats. Trade and business deals are expecting to focus on promoting more Chinese tourists to the Philippines and increasing Filipino food exports to China.
Mr Lopez had said $13.5bn (£11bn) in deals would be signed on the visit.
Mr Duterte has also said he would approach China to buy weapons and boats to upgrade the country’s military.
Relations between China and the Philippines had deteriorated over a territorial dispute in the South China Sea, after an international tribunal sided with Manila and rejected Beijing’s claims.
But on Thursday, the two countries said they would restart dialogue to resolve the dispute.
Although Mr Duterte maintained fiery rhetoric towards Beijing during his presidential campaign, he switched to a more reconciliatory tone after taking power in June.