U.S. President Donald Trump has called Philippine leader Rodrigo Duterte and expressed Washington's commitment to their treaty alliance and his interest in developing "a warm, working relationship," a Filipino official said Sunday.

Presidential spokesman Ernie Abella said Trump mentioned he was looking forward to visiting the Philippines in November to attend an East Asia summit that Duterte will host with several world leaders and that Trump invited Duterte to visit the White House.

"The discussion that transpired between the presidents was warm, with President Trump expressing his understanding and appreciation of the challenges facing the Philippine president, especially on the matter of dangerous drugs," Abella said in a statement.

A White House statement described late Saturday's call as "very friendly" and said the U.S.-Philippine alliance "is now heading in a very positive direction."

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