The Pakistani military says a technician at the country's main nuclear research facility has been killed in an explosion.
Khan's Kahuta plant is Pakistan's main nuclear weapons laboratory
Army spokesman Shaukat Sultan said the blast at the Khan Research Laboratories (KRL) occurred when the technician was handling conventional explosives.
He said there had been no damage to the nuclear facilities.
KRL was founded by Abdul Qadeer Khan, Pakistan's top nuclear scientist who admitted to leaking nuclear secrets.
Mr Sultan said the cause of Tuesday's blast at the facility in Kahuta near Islamabad was being investigated.
"It was a normal conventional explosive that he [the technician] was handling when the accident happened and he died," he said.
KRL is Pakistan's premier nuclear enrichment facility and was set up in the 1970s.
Regarded as a national hero for making Pakistan a nuclear power, Mr Khan admitted to leaking nuclear secrets to groups working for Iran, Libya and North Korea two years ago.
He was dismissed as a scientific adviser to the government following the revelations and has since lived under house arrest in Islamabad.
Pakistan's first nuclear power plant was built in 1972 in Karachi with Canadian assistance.
Western nations later ceased nuclear co-operation with Islamabad, after it was alleged Pakistan was developing nuclear weapons.
Pakistan conducted nuclear weapons tests in 1998, shortly after India carried out a number of nuclear tests. India tested its first nuclear weapon more than a decade earlier.