Philippine President Rodrigo Duterte announced his "separation" from the United States on Thursday, declaring he had realigned with China as the two nations agreed to resolve their South China Sea dispute through talks.

Duterte made his comments in Beijing, where he was visiting with at least 200 businesspeople to pave the way for what he calls a new commercial alliance as relations with longtime ally Washington deteriorate.

"In this venue, your honours, in this venue, I announce my separation from the United States," Duterte told Chinese and Philippine businesspeople to applause at a forum in the Great Hall of the People attended by Chinese Vice-Premier Zhang Gaoli.

"Both in military, not maybe social, but economics also. America has lost," Duterte said.

Duterte's efforts to engage China, months after a tribunal in the Hague ruled that Beijing did not have historic rights to the South China Sea in a case brought by the previous administration in Manila, marks a reversal in foreign policy since the 71-year-old former mayor took office on June 30.

His trade secretary, Ramon Lopez, said $13.5 billion in deals would be signed during the China trip.

The Obama administration agreed to a deal with Duterte's predecessor granting US forces rotational access to bases in the Philippines and further doubts will be raised about the future of this arrangement.

"The US-Philippine alliance is built on a 70-year history, rich people to people ties and a long list of shared security concerns," White House spokesman Eric Schultz told reporters. "We have not received any official requests from Filipino officials to alter any of our many issues where we bilaterally cooperate."

Schultz said the White House does not view Manila's relationship with China as a "zero sum game."

"We believe that it's in our national security interests when our partners and allies in the region have strong relationships with China," he said.

A few hours after Duterte's speech, his top economic policymakers released a statement saying that, while Asian economic integration was "long overdue", that did not mean the Philippines was turning its back on the West.

"We will maintain relations with the West but we desire stronger integration with our neighbours," said Finance Secretary Carlos Dominguez and Economic Planning Secretary Ernesto Pernia in a joint statement. "We share the culture and a better understanding with our region."

In response to Duterte's comments, US State Department spokesman John Kirby said: "We still hold that it is inexplicably at odds with the very close relationship that we have with the Filipino people, as well as the government there, on many different levels, not just from a security perspective.

"We are going to be seeking an explanation of exactly what the president meant when he talked about separation from the US. It's not clear to us exactly what that means in all its ramifications," Kirby told a daily briefing.

Kirby added that the US remains "rock solid in our commitment in the mutual defense treaty that we have with the Philippines. That hasn't changed," he said.

"This is a significant development, one that has been lost, at least for the moment, in the noise of the US presidential election," said Jon Taylor, professor of political science at the University of St Thomas in Houston.

"Obama has touted a pivot to Asia, primarily with the aim, frankly, of counterbalancing China. Instead, Duterte has pulled off his own pivot - in this case to China. This has some real implications for American influence in Asia and the Pacific," he said.

Taylor said in many respects this was not a complete surprise given the personal contention between Obama and Duterte.

"The invectives hurled by Duterte toward both Obama and the US in general should serve as a wake-up call to both the Obama administration and the likely winner of the US presidential election, Hillary Clinton. What will be interesting to see is their reactions in the coming days," Taylor said.

"Duterte has pushed a path that envisions far less dependence on the US. This will likely mean that China and the Philippines will reach an understanding for both mutual cooperation and accommodation of interests in the South China Sea, particularly fishing rights. It will open up Chinese infrastructure and economic investment in the Philippines as well as enhanced trade and tourism between the two nations," Taylor said.

The State Department also announced that Daniel Russel, the assistant secretary of state for East Asian and Pacific affairs, would be traveling to the Philippines this weekend.

But Kirby said the trip was long scheduled. "I don't want to give any impression that it was thrown on as a result of recent comments or activities. It was something he's been planning for months, but it does give us an opportunity in the context of these comments to try to get a better explanation of what was meant by 'separation' and where that's going," he said.

Douglas Paal, vice president for studies and director of Asia program at the Carnegie Endowment for International Peace, said some will view Duterte's remarks as the obituary for the Obama rebalance or pivot to Asia.

"Hillary Clinton's refusal to endorse the Trans-Pacific Partnership in her last debate reinforces the message," Paal said.

"If she is to be a successful president, she will have to get serious, rethink, and reshape her policy to conform to America's lasting interests and relationships in the Asia-Pacific region, including with the Philippines."

Contact the writer at chenweihua@chinadailyusa.com