Former US President Bill Clinton arrived in North Korea on Tuesday to try to negotiate the release of two US journalists convicted by the communist state of "grave crimes", South Korea's Yonhap news agency said.
The visit comes at a time of increasing militancy in the reclusive North which analysts say is in the midst of resolving leadership succession in Asia's only dynastic state as it refuses to return to multilateral talks on ending its nuclear ambitions.
The journalists were sentenced last month to 12 years' hard labour by the North after they were arrested at the border with China in March accused of illegal entry and being "bent on slander".
Euna Lee and Laura Ling, of US media outlet Current TV co-founded by former US Vice President Al Gore, were arrested when working on a story near the border between North Korea and China.
US officials fear that North Korea might try to use the journalists as leverage in trying to resist international pressure to halt its arms programme and weather U.N. sanctions over its missile and nuclear tests.
Some analysts have held out hope that Clinton's visit could end a cycle of provocative military action and lead to Pyongyang's return to fresh dialogue.
The North has declared dead long-troubled six-party talks aimed at reining in its nuclear arms programme with massive aid and diplomatic rewards but has made overtures in recent weeks seeking direct negotiations with Washington.
"As soon as he arrives, he will be entering negotiations with the North for the release of the female journalists," Yonhap quoted a source as saying about Clinton's trip.
South Korean Foreign Ministry officials declined to comment, saying any announcement would come from Washington or Pyongyang.
"We decline comment," White House spokesman Thomas Vietor said when asked about the report. The US State Department also declined to comment.
Clinton while in office sought to improve ties with the North, exchanging high-level envoys near the end of his term that fuelled expectations that Washington and Pyongyang would end decades of hostility and normalise ties.
Clinton's Secretary of State, Madeleine Albright, visited Pyongyang in 2000 and held talks with the North's supreme leader, Kim Jong-il, soon after his right-hand man and senior General Jo Myong-rok visited Washington.
The rapid improvement in ties was short lived as George W. Bush became US president and declared the North part of an "axis of evil" along with Iran and Iraq.
Kim Jong-il and his father and state founder Kim Il-sung have previously used visits by high-level US envoys to make the gesture of starting dialogue with Washington, said Yun Duk-min of the Institute of Foreign Affairs and National Security in Seoul.
"North Korea could come forward with the position that it would implement the Sept. 19 (nuclear disarmament) statement and eventually enter nuclear talks with the United States," he said.
Journalist Ling has told her sister by telephone that she and Lee broke North Korea's law. US Secretary of State Hillary Clinton, the former first lady, has said "everyone is very sorry" about the incident and urged Pyongyang to grant them amnesty.
North Korea has also held a South Korean worker for about four months accused of insulting the North's political system at a factory park jointly run by the rival Koreas.
It is also holding the four-man crew of a South Korean fishing boat that strayed north of a maritime border last week after experiencing navigational problems.
The stalled six-party talks brought together the two Koreas, host China, the United States, Japan and Russia.