A spokesman for Pakistan's foreign ministry rejected the allegations in a Washington Post article as "baseless."

"Pakistan strongly rejects the assertions in the article that is evidently timed to malign Pakistan and China," the spokesman said in a statement.

In written accounts cited by the newspaper, Abdul Qadeer Khan, who is the father of Pakistan's atomic bomb, 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.

The foreign ministry spokesman, however, slammed the report as an attempt to detract attention from India, Pakistan's arch atomic rival, which like Pakistan is not signatory to the Nuclear Non-Proliferation Treaty.

"This is yet another attempt to divert attention from the overt and covert support being extended by some states to the Indian nuclear programme since its inception and intensified more recently," he said.

Pakistan and China had "comprehensive and all-dimensional" cooperation, which includes civilian nuclear cooperation for peaceful purposes, he said.

"This has always been above board. Pakistan and China have always respected their respective international obligations and non-proliferation norms," the ministry spokesman said.

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.

Security arrangements have been imposed on Khan after a five-year period of house arrest for operating a proliferation network was lifted in February.