Assistant Secretary of State Daniel Russel, the top U.S. diplomat for East Asia, said Wednesday he did not know what a "panoply" of statements by Philippine President Rodrigo Duterte since taking office this year will mean for Manila's future security cooperation with Washington.

Duterte has made a series of conflicting statements about the future of his country's long-standing alliance with the United States. Last week he said U.S. President Barack Obama should "go to hell" and alluded to severing ties with Washington.

On Wednesday, in an apparent break from a weeks-long torrent of anti-American rhetoric, Duterte said the Philippines will maintain its existing defense treaties and its military alliances.