China on Monday called on the United States and North Korea to move ahead with stalled nuclear talks for regional stability, with Pyongyang having been putting pressure on Washington to change what it regards as one-sided demands by the end of this year.

Foreign Ministry spokesman Geng Shuang also said at a regular press briefing that “pressure and sanctions cannot resolve any problem,” apparently signaling for the United States to make concessions to achieve denuclearization of the Korean Peninsula.

Geng’s remarks came a day after Kim Yong Chol, vice chairman of the ruling Workers’ Party of Korea, issued a statement urging the United States to present a proposal within this year to break the impasse in bilateral negotiations.

North Korean leader Kim Jong Un and U.S. President Donald Trump have maintained close relations, but “there is a limit to everything,” Kim Yong Chol said in the statement carried Sunday by the official Korean Central News Agency.

“The U.S. is seriously mistaken if it is of the idea of passing off in peace the end of this year, by exploiting the close personal relations between its president and the Chairman of the State Affairs Commission of the DPRK for the delaying tactics,” Kim Yong Chol said.

DPRK is the acronym for North Korea’s official name, the Democratic People’s Republic of Korea.

During their summit in the Vietnamese capital of Hanoi on Feb, 27 and 28, Kim Jong Un and Trump fell short of bridging the gap between Washington’s denuclearization demands and Pyongyang’s calls for sanctions relief.

In a speech in April, Kim Jong Un asked the United States to shift its policy on denuclearization talks by the end of this year, criticizing Washington for making what he claimed are one-sided demands.

Earlier this month in Stockholm, the United States and North Korea resumed their working-level dialogue on denuclearization after months of stalemate but the talks ended without progress.

In recent months, North Korea has test-fired what appeared to be ballistic missiles, while warning that it may restart nuclear and intercontinental ballistic missile tests unless negotiations with the United States move forward later this year.

Pyongyang has been subject to international economic sanctions aimed at preventing the nation from developing nuclear weapons and ballistic missiles. North Korea’s economy is considered to be sluggish against a backdrop of the sanctions.

Meanwhile, China — North Korea’s closest and most influential ally — has indicated that it is willing to ease the sanctions, saying Pyongyang has already started to take concrete steps toward denuclearization.

The United States and North Korea technically remain in a state of war after the 1950-1953 Korean War ended in a cease-fire. The two countries have no diplomatic relations.

Since last year, Kim Yong Chol, a former military intelligence chief and close aide to Kim Jong Un, had led negotiations with the United States. After the collapse of the second U.S.-North Korea summit in February, he is believed to have left the front line.