Kerry says would be valuable for Trump to seek advice before calls

"We have not been contacted before any of these conversations. We have not been requested to provide talking points," Kerry said during a question-and-answer session at a think tank conference.

"I do think there’s a value, obviously on having at least the recommendations, whether you choose to follow them or not is a different issue, but I think it’s valuable to ask people who work the desk, and have worked it for a long period of time, their input on what’s the current state, is there some particular issue at the moment," Kerry added.

"I think that’s valuable, and I would certainly recommend it, but, obviously, that hasn’t happened in a few cases."

Trump's call with Taiwan President Tsai Ing-wen on Friday triggered a diplomatic protest from China and raised questions about whether the Republican president-elect might be signaling a change to U.S. policy. Vice President-elect Mike Pence denied that on Sunday, describing it as a "courtesy call."

The telephone conversation was the first by a U.S. president-elect or president with a Taiwanese leader since President Jimmy Carter switched diplomatic recognition to China from Taiwan in 1979, acknowledging Taiwan as part of "one China."

The diplomatic contretemps was one of several recently for Trump, a real estate magnate who has never held public office and has no foreign affairs or military experience. Trump, who takes office on Jan. 20, is still considering his choice for secretary of state.