A senior US arms control official said on Tuesday the only way for North Korea to achieve security and development is to abandon all of its weapons of mass destruction and ballistic missile programmes.

The Hanoi summit between US President Donald Trump and North Korea’s Kim Jong Un last month broke down over differences about US demands for Pyongyang to denuclearise, as well as Pyongyang’s demand for major relief from international sanctions imposed for its nuclear and missile tests, which it pursued for years in defiance of U.N. Security Council resolutions.

“North Korea must understand that the only way to achieve the security and development that it seeks is to abandon all of its weapons of mass destruction, all of its ballistic missile programmes as numerous U.N. Security Council resolutions demand,” said Yleem Poblete, US Assistant Secretary of State for Arms Control, Verification and Compliance.

Poblete, addressing the United Nations-sponsored Conference on Disarmament in Geneva, also urged countries to halt any weapons or military cooperation with North Korea.

“You are violating UN Security Council resolutions that explicitly prohibit such transfers,” she said without naming names.

North Korea is considering suspending talks with the United States and may rethink a freeze on missile and nuclear tests unless Washington makes concessions, a senior Pyongyang diplomat said last week, according to news reports from Pyongyang.

On Tuesday, a North Korean diplomat said there was no justification for maintaining full sanctions on Pyongyang given that it has halted nuclear and missile testing for the past 15 months.

Ju Yong Chol said that US-North Korean differences should be tackled one-by-one in a phased way to build trust.

“Instead, they came up with the preposterous argument that sanctions relief is impossible prior to denuclearisation,” Ju told the Geneva forum.

Meanwhile, a top security adviser to the South’s president said on Tuesday that North Korea should take “actual action” towards giving up its nuclear weapons to break the deadlock in talks with Washington, suggesting Seoul’s patience with Pyongyang may be wearing thin.

President Moon Jae-in was instrumental in brokering the negotiations between Pyongyang and Washington, seizing on the 2018 Winter Olympics in South Korea to catalyse a rapid diplomatic rapprochement after a year of missile tests, threats and tensions.

But the first summit between the North’s leader Kim Jong Un and US President Donald Trump in Singapore in June produced only a vague commitment to “work toward complete denuclearisation of the Korean peninsula.”

Their second meeting in Hanoi last month broke up without agreement, or even a joint statement, as the two failed to come to a deal over sanctions relief and denuclearisation.

Since then, Pyongyang has said it is considering suspending the talks and images have emerged of rebuilding works at the Sohae rocket launch facilities.

That triggered international alarm that North Korea might be preparing a long-range missile or space launch, which could put the whole negotiations process at risk − Pyongyang has not carried one out for more than a year and Trump has repeatedly said its continued moratorium is crucial.

A launch of any kind by the North would be a “disaster”, said Moon’s special adviser on national security Moon Chung-in.

The “outcome will be catastrophic”, he told reporters.

In Hanoi, US officials said, Trump urged Kim to “go all in” and that “the weapons themselves need to be on the table”. In return, they were “prepared to go all in as well”.

But it was not clear exactly which facilities at the Yongbyon nuclear complex the North was willing to give up, while they wanted “basically all the sanctions except for armaments” lifted, the officials said.

For its part the North’s foreign minister said it only wanted some of the measures eased, and that its proposal to close “all the nuclear production facilities” at Yongbyon was its best and final offer.

Ju Yong Chol, a North Korean diplomat responding to a speech by a senior US arms control official at the UN-sponsored Conference on Disarmament, said that issues between the two countries should be addressed one-by-one so as to build trust.

Agencies