US nuclear negotiator Christopher Hill visits North Korea today (October 1) in an effort to salvage a stalled disarmament accord, saying negotiations with the communist nation have reached a "very tough phase," reported Bloomberg News.

Hill will press officials in North Korea's capital, Pyongyang, to agree to a verification system to check the extent of the regime's nuclear program. "We've put together a draft to that regard," he told reporters late yesterday in Seoul, after flying in from Washington.

Disarmament talks have been stalled since Kim Jong-il's regime in August stopped disabling the Yongbyon reactor, the source of its weapons-grade plutonium, to protest delays at being removed from a US terrorism blacklist.

The Bush administration says North Korea, which tested a nuclear bomb in 2006, will remain on the list until a verification system is in place. South Korea, China, Japan and Russia are the other parties to the talks.

Hill will present the North Koreans with a face-saving proposal in an effort to break the deadlock, the Associated Press reported yesterday, citing an unidentified senior US official in Washington.

Under the plan, Kim's regime would agree to a verification programme and submit it first to China, AP reported. The US would then provisionally remove North Korea from the terrorism list, the news agency said.

"We are going to talk about what we need on verification," Hill told reporters in Seoul when asked if he would submit a plan to officials in Pyongyang.