MANILA, Philippines — America’s top 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.

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.

In a major walk-around, 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.