WASHINGTON - BILL Clinton on Tuesday gave President Barack Obama a tantalising insider's account of his talks with reclusive North Korean leader Kim Jong Il and his trip to free two jailed US journalists in Pyongyang.

The former president returned to the secure White House Situation Room, where he once tackled US national security crises himself, to brief Mr Obama and top foreign policy and intelligence aides on his mission earlier this month.

The pair then headed to the Oval Office to continue their conversation for another half-hour, White House spokesman Robert Gibbs said. Mr Obama thanked Mr Clinton in person for 'undertaking the humanitarian mission to secure the release of two American citizens who had been detained by North Korea for over four months,' Mr Gibbs said in a statement.

'President Obama said he was gratified that the Americans had been safely reunited with their families.' Mr Clinton, Mr Gibbs said, described the mission, which included a meeting with North Korea's 'Dear Leader' who ultimately granted Laura Ling and Euna Lee 'special amnesty' and allowed them to return to the United States.

The White House gave no further details of Mr Clinton's sensitive mission to free the jailed reporters, or the treasure trove of intelligence Mr Clinton brought back with him.

Mr Gibbs said Mr Clinton has conducted several in-depth briefings for top US national security officials desperate for first-hand intelligence on the political machinations inside the hermit state.

Prior to Tuesday's meeting, Mr Clinton only had the chance to talk to Mr Obama briefly on the telephone since returning home with the pair.

Senior national security officials at the meeting of past and present presidents included National Security Adviser James Jones, Tom Donilon - one of Mr Jones's deputies - and White House proliferation experts.

The former president's wife, Secretary of State Hillary Clinton, was not there due to what officials described as scheduling conflicts, but was represented officially by Cheryl Mills, her chief of staff. The US diplomatic chief also had a private meeting scheduled with Mr Obama on Tuesday.

US intelligence analysts have been awaiting a priceless briefing on the state of Mr Kim's mind, health and regime from one of America's most seasoned diplomatic players.

The White House has insisted that Clinton's visit was a purely private affair and denied he delivered a message from Mr Obama as Washington seeks ways to cool the showdown over Pyongyang's nuclear and missile programmes.