Barack Obama sends letter to North Korea's Kim Jong-Il

The US president's special envoy, Stephen Bosworth, delivered the letter while visiting Pyongyang last week for three days of discussions with officials.

Obama hopes to encourage North Korea to return to talks over denuclearisation. The country left aid-for-disarmament discussions a year ago, vowing never to return. It subsequently tested a nuclear device in May.

A senior US official, who confirmed Bosworth handed North Korean officials a personal letter from Obama and who spoke under the condition of anonymity, would not describe the contents of the letter but said they fitted with the envoy's message.

"The North Koreans have a choice: continued and further isolation or benefits for returning to the six-party talks and dismantling their nuclear weapons programme," he said. He was unaware whether the North Korean leader had responded.