MANILA » A top American diplomat for Asia said Monday that Philippine President Rodrigo Duterte’s controversial remarks and a “real climate of uncertainty” about his government’s intentions have sparked distress in the U.S. and other countries.

Daniel Russel, the assistant secretary of state for East Asian and Pacific affairs, said he also relayed to Philippine Foreign Secretary Perfecto Yasay Jr. international concern over continuing killings under Duterte’s crackdown against illegal drugs. In addition, Secretary of State John Kerry spoke by phone Sunday with Yasay about “recent challenges” in bilateral relations, the State Department said.

Russel’s visit to the Philippines, part of a three-nation trip to Southeast Asia, comes amid increasing uncertainty about Washington’s treaty alliance with Manila. The brash Duterte, who took office on June 30, has displayed antagonism toward America, declaring his desire to scale back military engagements with the U.S. and telling President Barack Obama to “go to hell.”

Duterte’s administration, however, has not formalized his public declarations to remove U.S. counterterrorism forces from the volatile southern Philippines and stop large-scale joint exercises involving American forces, creating confusion among even his Cabinet officials.

Duterte sparked diplomatic alarm when he announced during a state visit to Beijing last week his “separation” with the United States. Upon returning home the next day, Duterte said he did not mean he was severing diplomatic ties with Washington but only wanted to end a foreign policy that’s overly oriented toward the U.S.

“I’ve pointed out to Secretary Yasay that the succession of controversial statements, comments and a real climate of uncertainty about the Philippines’ intentions has created consternation in a number of countries, not only in mine,” Russel told reporters in Manila after an extended meeting with Yasay.

The unease, Russel said, was also palpable “not only among governments, but also … in other communities, in the expat Filipino community, in corporation boardrooms as well.”

“This is not a positive trend,” he said, adding that the U.S. remains committed to continuing a solid alliance with and providing assistance to the Philippines, including in fighting drug crime.

State Department spokesman John Kirby, however, said both Kerry and Russel came away from their discussions “feeling that we are going to be able to work through this period.” Kirby said the U.S. remains committed to its mutual defense treaty with the Philippines.

Coinciding with Russel’s visit, the U.S. military turned over a refurbished C-130T cargo plane as part of Washington’s effort to help modernize the underfunded Philippine military, which has struggled to deal with Muslim and communist insurgencies and natural disasters.

Outgoing U.S. Ambassador Philip Goldberg said at the turnover ceremony that the U.S. was trying to clarify Duterte’s remarks in relation to existing policies, including their impact on planned joint military exercises. Despite the concerns, Goldberg said the U.S. rebalance to Asia would proceed.

“It’s a historical relationship, it has its ups and downs,” Goldberg told reporters. While he remains optimistic, Goldberg said “some of the language we’ve heard is inconsistent with that friendship.”

Asked if joint combat exercises with the Americans would continue despite Duterte’s declared opposition to them, Yasay could not give a categorical answer.

Duterte wanted the joint combat drills to enable the Philippines “to be self-reliant in our defensive requirements,” Yasay said. “If this will not be achieved, (Duterte) said then, there’s no purpose of proceeding with these.”

Patrolling the China-held Scarborough Shoal with the U.S. Navy, for example, can send a signal that it’s a deterrent against bad Chinese intentions. “It has precisely resulted in both parties digging in and made a peaceful resolution of the disputes even farthest from achieving,” Yasay said.

Russel said that while Washington welcomes the relaxation of tensions between Manila and Beijing under Duterte, the rapprochement should not come at the expense of the U.S. or other nations.

“It’s a mistake to think that improved relations between Manila and Beijing somehow come at the expense of the United States,” he said. “This should be addition and not subtraction.”

Duterte said Sunday that Filipino fishermen “may” be able to return to Scarborough in a few days after he discussed the territorial rift with Chinese leaders in Beijing last week, but he did not say whether China imposed conditions. China also committed to provide up to $16 million in financial assistance primarily for agriculture, aside from business deals with Philippine companies, he said, praising China’s kindness.

Asked whether China would allow Philippine fishermen access to Scarborough, Chinese Foreign Ministry spokesman Lu Kang made no commitments on Monday.

“So I can assure you that, with sufficient political will on both sides, all issues between China and the Philippines can be resolved appropriately,” Lu said.

Associated Press writers Christopher Bodeen in Beijing and Matthew Pennington in Washington contributed to this report.