Kim Jong Un and Donald Trump
Kim Jong Un and Donald TrumpReuters

US special envoy for North Korea, Stephen Biegun, on Sunday night called on Pyongyang to return its offer of talks, saying Washington is willing to discuss “all issues of interest.”

Biegun, speaking at a joint news conference in Seoul with his South Korean counterpart Lee Do-hoon and quoted by Reuters, said the United States did not have a “deadline” but wanted to reopen negotiations.

“It is time for us to do our jobs. Let’s get this done. We are here, and you know how to reach us,” the envoy said.

Tension has been rising between Washington and Pyongyang in recent weeks as North Korea has conducted a series of weapons tests and waged a war of words with US President Donald Trump.

On Saturday, North Korea said it had successfully conducted another test at a satellite launch site and added its latest tests are aimed at “restraining and overpowering the nuclear threat of the US”.

Trump and North Korean leader Kim Jong Un engaged in months of mutual insults and threats of devastation in 2017, sending tensions soaring before a diplomatic rapprochement the following year.

The pair have met three times since June 2018, most recently in Vietnam in February, but with little progress towards denuclearization. Pyongyang has set Washington a December 31 deadline to make new concessions to kickstart stalled talks.

Since that June meeting, North Korea has conducted several tests of ballistic missiles.

Trump warned last week that Kim had "everything" to lose through hostility towards the United States.

"Kim Jong Un is too smart and has far too much to lose, everything actually, if he acts in a hostile way," Trump tweeted.