Islamabad, Feb. 10: Under rising international pressure, the Pakistan Government has imposed a fresh set of restrictions on disgraced nuclear scientist Dr Abdul Qadeer Khan.

Khan, who was acquitted by the Islamabad High Court of charges of nuclear proliferation last week, faces new restrictions on his movement and contacts.

"The vigilance outside AQ Khan's residence has been beefed up and visitors are not allowed. He has been barred from travel and allowed to receive visitors only from an approved list of family and friends," The Nation quoted a private television channel, as saying.

The Pakistan Interior Ministry has said that it will monitor Dr. Khan's telephone calls, visitors and activities.

Washington has expressed serious concern over the high court order. Despite Islamabad's assurances, a US official said Washington is still uncertain about the new arrangement.

"We're very concerned, Pakistan has given us some initial commitments but we're going to follow the situation very closely. The important thing is that they know we are still very serious about this ( A. Q. Khan) individual," a US official said. (ANI)