A senior North Korean official on Tuesday warned of an "undesired consequence" for the U.S. if Washington does not adjust its policy on North Korea's denuclearization by an end-of-the-year deadline leader Kim Jong Un has set.

"Our determination for denuclearization remains unchanged, and when the time comes, we will put it into practice. But, this is possible only under the condition that the U.S. changes their current method of calculation and formulates a new stand," North Korean First Vice Foreign Minister Choe Son Hui, a key figure in nuclear negotiations with the United States, was quoted by the North's state-run Korean Central News Agency as saying.

The nuclear talks have stalled since the second summit between Kim and U.S. President Donald Trump collapsed in February with no deal on the North's denuclearization.