By David Brunnstrom

WASHINGTON (Reuters) - The top U.S. diplomat for East Asia said on Wednesday he did not know what a "panoply" of statements by Philippine President Rodrigo Duterte since taking office this year would 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 would maintain its existing defense treaties and its military alliances.

But he added to the confusion when he said his foreign policy was to "realign" and reiterated that joint exercises with U.S. troops, a decades-old tradition, would be stopped.

Obama's senior U.S. diplomat for East Asia, Assistant Secretary of State Daniel Russel, told a roundtable discussion with Washington defense journalists he was baffled.

"President Duterte has made a panoply of statements; I think the operative adjective is 'colorful,'" he said.

"But what that will ultimately translate (into) in terms of the ability of the Philippines to work with the United States on issues directly germane to security and even some of the regional and global challenges it faces ... we don’t have an answer to just yet."

Russel said he was not aware of any changes in security cooperation but added, "I’m not saying it couldn’t happen, it wouldn't happen."

He said that if the Philippine government were to propose specific changes to the relationship, the United States would "deal with that," but said there was "a distinction to be made between general high level pronouncements and considered policy decisions and actions."

"There is a lot of noise, there’s a lot of stray voltage in the media, but ultimately the decisions about the alliance operations are going to be taken, I believe in a deliberate and thoughtful way."

Russel said the United States was "working through" the uncertainty and added that the two countries had "been through a lot worse in our 70-year history."

He said the U.S. relationship brought "tremendous" benefits to the Philippines ranging from cooperation on counter-terrorism and combating illegal fishing to dealing with Manila's territorial disputes with China in the South China Sea.

Russel said Manila's developing dialogue with China was "in principle" a good thing, provided it was conducted on terms acceptable to the Philippines and consistent with international law.

(Reporting by David Brunnstrom; Editing by Andrew Hay)