The United States reassured China on Thursday that it will continue to uphold its "one-China" policy, amid heightened tensions between the major powers before U.S. President-elect Donald Trump's inauguration later this month.

In his phone conversation with Chinese Foreign Minister Wang Yi, U.S. Secretary of State John Kerry said bilateral ties are "very important" and adhering to the policy is a "common stand" of both the Democratic and Republican parties, Wang's ministry said in a statement.

Wang said China-U.S. ties are at an "important stage" and the two countries should make efforts to maintain the "correct direction" for their development, according to the ministry.

The conversation took place at a delicate time as Trump, who will assume office on Jan. 20, has indicated that his administration will not necessarily be bound by Washington's nearly four-decade policy of recognizing that Taiwan is part of China.

China has grown anxious about Trump's incoming administration since he spoke by phone with Taiwan President Tsai Ing-wen early last month, believed to be the first conversation between a U.S. president or president-elect and a Taiwanese leader since Washington switched diplomatic recognition from Taipei to Beijing in 1979.

China regards Taiwan as a renegade province awaiting reunification, by force if necessary.

In the phone call, which the ministry said it was held at the request of the U.S. side, Wang and Kerry also discussed international and regional issues of mutual concern.

North Korea was most likely a topic touched on by them, given that the country's leader, Kim Jong Un, said Sunday that its preparations to test-fire an intercontinental ballistic missile have reached the "final stage."