The United States has been engaging in back-channel diplomacy with North Korea for several months in efforts to resolve the North’s nuclear issue, according to the Associated Press.

The AP reported on Friday, citing unidentified U.S. officials and others briefed on the process, that the dialogue involved Joseph Yun, the U.S. envoy for North Korea policy, and Pak Song-il, a senior North Korean diplomat at the United Nations.

It said dialogue between Washington and Pyongyang was completely cut off during the last seven months of the Obama administration but since Donald Trump took office, “talks for talks’ sake” were resumed as both sides were willing to engage in dialogue.

This shows a dialogue channel has been maintained with the North under the Trump administration even while the two sides have stepped up their rhetoric and warnings amid rising tensions in the region.

The White House and the State Department have both said they cannot confirm the AP report.