By Zaffar Abbas BBC correspondent in Islamabad

The relatives fear the detainees will be handed to the US

The High Court in Lahore was ruling in response to four habeas corpus petitions filed by families of the scientists and officials.

Relatives fear the detainees may be handed to the US or other countries.

The Pakistani Government says there are no plans for extradition or to involve any foreign investigators.

It says the results of its inquiry into the possible transfer of nuclear technology to Iran and other nations will be completed in a week.

Restraining order

Family members and supporters of four of the detained scientists and officials of the country's main nuclear establishment, Khan Research Laboratories, were in court for Friday's hearing.

Justice Anwar ul-Haq did not initially act on the habeas corpus petitions.

However, after fears were expressed by one of the petitioners' lawyers that those detained could be extradited, the judge decided to issue a restraining order.

The government assured the relatives no extradition was planned

The government was instructed not to move them anywhere outside the court's jurisdiction.

The petitioners described the detentions as unlawful and told the court that they had not even been informed of the whereabouts of the detainees.

The government says a small number of scientists and officials have been taken in for "debriefing" as part of the investigation.

So far more than a dozen people have been questioned, including the country's foremost nuclear scientist, Abdul Qadeer Khan.

Information Minister Sheikh Rasheed Ahmed said there were no plans to extradite any of the scientists or to involve the FBI or foreign investigators in the probe.

He said nine scientists and officials were being held by the authorities for more questioning.

Mr Ahmed said the probe would probably be completed within a week, after which it would become clear if any individual had been involved in the illegal transfer of nuclear information to a third country.

The government says its investigation started more than a month ago after the International Atomic Energy Agency shared information with Pakistan on the possible transfer of technology to Iran and Libya several years ago.