North Korea has threatened to pull out from the 2007 disarmament deal and restart plutonium production at its Yongbyon nuclear complex, accusing the United States of reneging on a pledge to strike the country off its list of state sponsors of terrorism.
The U.S. insists on a tougher verification of the North's denuclearization progress before removing it from the terrorism list, which enforces major trade restrictions. The Yongbyon plant has been largely dismantled in return for economic aid and diplomatic incentives under the six-nation deal.
In Seoul on Tuesday, Hill outlined the purpose of his third trip to North Korea: "We are going to try to get through phase two, namely the need to have an agreement on what verification will look like."
However, Yonhap quoted a diplomatic source as saying later that Hill's primary mission is to persuade North Korea to stop the restoration of its nuclear facilities. "The U.S. has come up with a revised draft verification protocol," the source said. "Hill will try to reach a compromise on it."
Hill was cautious about the prospects for his trip's outcome, the agency said.
"I can't really tell you what is going to happen in Pyongyang," Yonhap quoted Hill as saying. "We had some discussions through the New York channel (the North Korean mission to the UN). We thought it would be useful to try to have the discussions in Pyongyang and that's why I'm going. So let's see if we can make some progress on this."
Yonhap also cited a South Korean security source as saying that increased activity has been spotted near the site of North Korea's 2006 nuclear bomb test, prompting suspicions that Pyongyang could be repairing the facility for a second test explosion.
"We recently witnessed smoke near the nuclear test site in Poongkye-ri, North Hamkyong Province," the news agency quoted a source as saying.
Smoke over the nuclear test site could be a cover against spy satellites, the source told the agency.
