Prospects for making any headway on the North Korean nuclear crisis this week are gloomy, diplomats and analysts say, after a 37-day recess in the six-party talks during which both Pyongyang and Washington have dug in their heels.

Despite an encouraging start to the fourth round of talks aimed at persuading North Korea to abandon its nuclear weapons, negotiations have become bogged down over whether Pyongyang should be allowed to use nuclear energy for peaceful purposes.