The United Nations Security Council has unanimously boosted sanctions on North Korea since 2006 in a bid to choke funding for Pyongyang’s nuclear and ballistic missile programs, banning exports including coal, iron, lead, textiles and seafood, and capping imports of crude oil and refined petroleum products.

Under the sanctions, 12 North Koreans are subject to a global travel ban and asset freeze. While it was not known if any of them will travel to Vietnam, the council’s North Korea sanctions committee approved Vietnam’s request for a blanket exemption, according to an internal document dated Tuesday seen by Reuters.

The approval allows the participation of the North Korean delegation in the February 27 and 28 summit and preparation work in Vietnam beforehand.

Trump and Kim first met in Singapore in June, but the summit produced only vague commitments from Kim and little concrete progress since toward denuclearization.

A confidential report to the Security Council by U.N. sanctions monitors earlier this month found that North Korea’s nuclear and ballistic missile programs remain intact and the country is working to make sure those capabilities cannot be destroyed by any military strikes.

Washington has been demanding that North Korea give up a nuclear weapons program that threatens the United States, while North Korea has been seeking a lifting of punishing sanctions, a formal end to the 1950-53 Korean War and security guarantees.

Since the Singapore summit, Russia and China suggested the Security Council discuss easing sanctions on North Korea as a reward and encouragement toward denuclearization. But the United States and other powers say sanctions must be enforced until there is full denuclearization.

Russia has also blamed U.N. sanctions for creating "serious humanitarian problems" in North Korea.

"We need to encourage humanitarian supplies to North Korea. We think that it is appropriate to encourage them economically and that might necessitate lifting, at least partially, some of the sanctions," Russian U.N. Ambassador Vassily Nebenzia told reporters on Wednesday.

He said Moscow hoped the Vietnam summit would end with a positive result but added: "You cannot expect to solve it at a two-day meeting, this is a long road."