WASHINGTON (Reuters) - The United States has told its ally South Korea it should not improve ties with North Korea faster than Pyongyang takes steps to give up its nuclear weapons, U.S. Secretary of State Mike Pompeo said on Tuesday.

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Speaking as a working group with South Korea to coordinate North Korean policy held an inaugural meeting in Washington, Pompeo indicated that Washington had been concerned that Seoul had moved too quickly with Pyongyang.

“We have made clear to the Republic of Korea that we do want to make sure that peace on the peninsula and the denuclearization of North Korea aren’t lagging behind the increase in the amount of inter-relationship between the two Koreas,” he told a news briefing.

“We view them as tandem, as moving forward together,” Pompeo added. “We view them as important parallel processes, and that working group is designed to make sure they continue to remain that way.”

The working group is headed by South Korea’s special representative for Korean Peninsula peace and security affairs, Lee Do-hoon, and Stephen Biegun, the U.S. special representative for North Korea.

Pompeo said he believed there was “complete agreement” on how to proceed.

South Korea’s Yonhap news agency quoted a statement from Seoul’s Foreign Ministry as saying the two sides in the meeting agreed to continue close coordination and cooperation on an “increasingly systemic and regular basis.”

Last month, in a rare sign of discord between Seoul and Washington, South Korean Foreign Minister Kang Kyung-wha said Pompeo had expressed “discontent” at an inter-Korean military pact reached during a summit in September.

The Koreas also agreed in October to begin reconnecting rail and road links despite U.S. concerns that the rapid North-South thaw could undermine efforts to press Pyongyang to give up its nuclear weapons.

At an unprecedented summit in June, U.S. President Donald Trump and North Korean leader Kim Jong Un agreed to work toward denuclearization and peace on the Korean peninsula and establish new relations.

But negotiations have since made little headway, with Pyongyang upset by Washington’s insistence that international sanctions must remain until it gives up its nuclear weapons.

Last week, South Korean Unification Minister Cho Myoung-gyon said in Washington it was important to provide North Korea with motivation to denuclearize but that sanctions would stay in place “until we see actual progress on denuclearization.”