SEOUL--The U.S. special envoy for North Korea, Stephen Biegun, urged Pyongyang on Monday to return offers of talks, dismissing leader Kim Jong Un's year-end deadline while highlighting Washington's willingness to discuss "all issues of interest."

Tension has been rising in recent weeks as Pyongyang has conducted a series of weapons tests and waged a war of words with U.S. President Donald Trump, stoking fears the two countries could return to a collision course that they had been on before launching diplomacy last year.

Biegun arrived in Seoul on Sunday amid speculation he might try to salvage negotiations by reaching out to North Korea, which has vowed to take an unspecified "new path" if Washington fails to soften its stance before the end of the year.

"The United States does not have a deadline. We have a goal," Biegun told a joint news conference with his South Korean counterpart Lee Do-hoon.

"Let me speak directly to our counterparts in North Korea. It is time for us to do our jobs. Let's get this done. We are here, and you know how to reach us," Biegun said.

Biegun said it would be "most unhelpful" if North Korea carries out a major military provocation in the near future.

He also expressed regret over a string of statements from North Korean officials in recent weeks, saying the tone of them has been "so hostile and negative and so unnecessary."

On Sunday, Pyongyang said it had successfully conducted another test at a satellite launch site aimed at "restraining and overpowering the nuclear threat" of the United States, which experts said could help North Korea build more reliable intercontinental ballistic missiles.

"But it does not have to be this way. It is not yet too late," Biegun said.

"We have offered any number of creative ways to proceed with feasible steps and flexibility in our negotiations to reach balanced agreements that meet the objectives of both sides."