In written accounts cited by the newspaper, Abdul Qadeer Khan said China also supplied a blueprint for a simple bomb that significantly speeded Pakistan's nuclear weapon program.

The Post said the deliberate act of proliferation was the culmination of a secret nuclear deal struck in 1976 by Chinese leader Mao Zedong and Pakistan's prime minister Zulfiqar Ali Bhutto.

"Upon my personal request, the Chinese Minister ... had gifted us 50 kg [kilograms] of weapon-grade enriched uranium, enough for two weapons," Khan wrote in what the Post said was a previously undisclosed 11-page narrative of the Pakistani bomb program.

Khan prepared the narrative for Pakistani intelligence officers after his January 2004 detention for unauthorized nuclear commerce. He is still under house arrest.

In a separate account sent to his wife several months earlier, he wrote, "The Chinese gave us drawings of the nuclear weapon, gave us kg50 enriched uranium."

The Post said China has long denied helping any other nation acquire nuclear weapons, but that Khan's accounts confirm the long-held conclusion of US intelligence that China provided such assistance.

US President Barack Obama is expected to raise nuclear proliferation issues with China when he visits Beijing on Tuesday.

Khan, the alleged mastermind of a nuclear proliferation network that stretched to Libya and possibly Iran, stated that top politicians and military officers were immersed in Pakistan's foreign nuclear dealings, the Post said.

"The speed of our work and our achievements surprised our worst enemies and adversaries and the West stood helplessly by to see a Third World nation, unable even to produce bicycle chains or sewing needles, mastering the most advanced nuclear technology in the shortest possible span of time," Khan boasts in the 11-page narrative.