UNITED NATIONS (Reuters) - Russia has asked the United Nations Security Council to discuss North Korea sanctions on Thursday, diplomats said, a move that comes after a planned meeting between top U.S. and North Korean officials in New York this week was postponed.

It was not immediately clear why Russia wanted the council to discuss the issue, though China’s foreign ministry said last month that Beijing, Moscow and Pyongyang believed it necessary to consider adjusting the U.N. sanctions at an appropriate time.

The 15-member Security Council has unanimously boosted sanctions on North Korea since 2006 in a bid to choke off funding for Pyongyang’s nuclear and ballistic missile programs.

China and Russia have said the council should reward Pyongyang for the “positive developments” after U.S. President Donald Trump and North Korean leader Kim Jong Un met in June and Kim pledged to work toward denuclearization.

But the United States and other Western powers have said sanctions must be enforced until there is full denuclearization. U.S. Ambassador to the United Nations Nikki Haley has also accused Russia of cheating on U.N. sanctions on North Korea.

U.S. Secretary of State Mike Pompeo had been due to meet senior North Korean official Kim Yong Chol in New York on Thursday to try to pave the way for a second summit between Trump and Kim and make progress on denuclearization.

The State Department announced on Wednesday that the talks would be rescheduled, but gave no reason for the delay. North Korea’s U.N. mission did not immediately respond to a request for comment on the postponement of the talks.

North Korea’s foreign minister told the United Nations in September that continued sanctions were deepening its mistrust of the United States and there was no way the country would give up its nuclear weapons unilaterally under such circumstances.

In July, Russia and China delayed a U.S. push for the Security Council’s sanctions committee to order a halt to refined petroleum exports to North Korea, asking for more detail on a U.S. accusation that Pyongyang had breached sanctions, diplomats said.