Seoul - North Korea is preparing to test-fire an intercontinental missile capable of carrying a nuclear warhead, South Korean media reports said Tuesday.

Intelligence agencies in South Korea and the United States observed a train carrying a large cylindrical object that was believed to be a Taepodong-2 missile, the South Korea news agency Yonhap reported, citing an intelligence source.

The launch was expected in one or two months, Yonhap quoted the source as saying.

The Taepodong-2, when technically perfected, could reach the US state of Alaska and carry a nuclear warhead, according to the US military.

The reports appeared at a time of rising tensions between North and South Korea and immediately after a new administration took office in the United States as the two allies seek to coax North Korea back to the nuclear negotiating table.

On Friday, North Korea said it was scrapping all inter-Korean peace accords signed to usher in reconciliation and ease military tensions along the heavily fortified inter-Korean border.

Relations between Seoul and Pyongyang have been on a downward slide since conservative South Korean President Lee Myung Bak took office almost one year ago. He has adopted a tougher stance against North Korea and ditched his predecessor's reconciliation "sunshine policy" toward Pyongyang.

North Korea test-fired a Taepodong-2 missile in July 2006 from its east coast, but the United States said the launch failed.

Three months later, North Korea carried out its first nuclear test, which was condemned worldwide. (dpa)