ISLAMABAD, Jan 19: The government has barred officials of the Khan Research Laboratories from travelling abroad after several of their colleagues were picked up for what is being termed "debriefing," an official said on Monday.

Even KRL chairman Javed Ashraf Mirza's request for going to Saudi Arabia for performing Haj was turned down, the source said, adding all senior KRL officials were under high stress.

Family members of KRL officials, picked up by an intelligence agency on Saturday, said they did not know whereabouts of these officials since they were taken under the custody.

Muhammad Usman, son of former director-general of KRL's science and technology cooperation department Dr Nazir, who was presently working as an assistant of Dr Abdul Qadeer Khan, said he had contacted the KRL chief for help.

"The response of Mr Mirza was not satisfactory because he, too, seems to be helpless in protecting senior officials, who have served the KRL for two decades," he said. Mr Usman said he also met foreign office spokesman Masood Khan and asked for his father's whereabouts. He quoted the spokesman as saying: "Your father is safe and sound and he would return within two or three days."

Mr Usman also quoted the spokesman that these officials were picked up for debriefing as part of internal security measures. A family member of Islamul Haq, principal staff officer of Dr Abdul Qadeer Khan, said even the KRL chief did not know Mr Haq's whereabouts.