The White House said it has not received any official requests from Manila to change cooperation between the two countries. But Duterte’s “anti-U.S.” sentiments and statements have caused anxiety in Washington.

The U.S. seems to have been caught off guard by Duterte’s announcement that the Philippines would separate from the U.S.

U.S. Assistant Secretary of State is travelling to Manila this weekend on a pre-planned trip where he will meet with counterparts to assess the situation.

“We are going to be seeking an explanation of exactly what the president meant when he talked about separation from the U.S.; it’s not clear what that means and all its ramifications,” U.S. assistant secretary of State John Kirby said.

The U.S. military treaties with the Philippines dating back to the 1950s including the Enhanced Defense Cooperation Agreement that was signed two years ago. It allows for U.S. troops and equipment access to Filipino military bases. The U.S. wants to know if these treaties are in jeopardy and if the Philippines might expel U.S. troops from the country.