The US government on Monday summoned the charge d'affaires of the Philippine Embassy to clarify what it called "inappropriate comments" made by Philippine President Rodrigo Duterte about US Ambassador Philip Goldberg.

"We've seen those inappropriate comments made about Ambassador Goldberg," said US State Department spokeswoman Elizabeth Trudeau.

But she declined to disclose the details of the conversation between US officials and Patrick Chuasoto, the Philippines charge d'affaires in Washington.