The country's official news agency reported that the journalists, Lisa Ling and Euna Lee, documented their journey into communist North Korea, even pocketing a stone to commemorate the illicit trip across the frozen Tumen River from China.

'We've just entered a North Korean courtyard without permission,' the Korean translation of their videotape narration said, according to Korean Central News Agency.

Ms Ling, 32, and Ms Lee, 36, who work for former Vice President Al Gore's California-based Current TV media group, were sentenced last Monday to 12 years of hard labour in a North Korean prison for illegal entry and 'hostile acts.' Before Tuesday's report, little was known publicly about the journalists' arrest March 17.

The timing of its release - just hours before President Barack Obama met with South Korea's leader Lee Myung-bak and days after the UN Security Council issued new sanctions against North Korea for a May nuclear test - raised fears the women were being used as political pawns.

North Korea wants to remind the US that the women remain in Pyongyang's hands, said Kim Yong-hyun, a professor at Seoul's Dongguk University.

'The North is sending a message ahead of the summit: 'Don't take your eyes off this. This is a negotiating card we have,'' Prof Kim said.

KCNA said it released the report to 'let the world know crimes committed by Americans at a time when an unprecedented confrontation with the United States has been created on the Korean peninsula.' 'The accused admitted that what they did were criminal acts, prompted by the political motive to isolate and stifle the socialist system of the DPRK by faking up moving images aimed at falsifying its human rights performance and hurling slanders and calumnies at it,' the agency said. The DPRK stands for the Democratic People's Republic of Korea.

Brent Marcus, a spokesman for Current TV, said the company had no comment on the developments. A spokesman for Mr Gore also declined comment.

KCNA warned Washington that North Korea was watching its next moves closely.

'We are following with a high degree of vigilance the attitude of the US which spawned the criminal act' against North Korea, the report said. -- AP