Two US reporters detained for almost five months in North Korea have indicated that their arrest may have been a premeditated trap laid by Pyongyang, as the regime looked for bargaining chips in a stand-off over its nuclear programme.

North Korean soldiers grabbed Laura Ling and Euna Lee, journalists for San Francisco-based Current TV, as they were making a documentary on the frozen river Tumen that forms the border with China. They were detained from March until last month, when former US president Bill Clinton secured their release on a trip to Pyongyang.