Disgraced Pakistani nuclear scientist A Q Khan was admitted to a hospital for emergency medical tests after his health deteriorated.

Khan, 66, who recently underwent surgery for prostrate cancer, developed sudden pain in his femoral vein on Thursday, following which doctors were called in for an emergency medical check-up, Pakistan's Online news agency reported.

He underwent tests at Khan's Research Laboratories, the country's premier agency that controlled Pakistan's nuclear programme.

On medical advise he was taken to a hospital from his highly guarded residence. After the medical examination, the physicians advised that he needed to be shifted to intensive care for a detailed examination, it said, adding that he was later brought back home after two days.

A thorough medical examination revealed that Khan had a blood clot in his vein and it could have been dangerous and caused a heart attack or brain haemorrhage, it said.

Khan's family members said that they were worried about health. They said the antibiotics administered to him during treatment of prostate cancer had thickened his blood 'to an extent that could be characterised as dangerous', local daily Dawn reported.

Pakistan defence spokesman Major General Shaukat Sultan said the scientist was being provided constant medical care and medical checkups were conducted whenever needed.

Khan has been accused of proliferating nuclear technology to countries like North Korea.