Pakistani nuclear scientist Abdul Qadeer Khan, who was released on Friday from five years of house arrest for selling nuclear secrets, faces a new set of restrictions on his movement and contacts, according to Pakistani officials.

Under an agreement reached among Khan’s lawyers, the judge who ordered him released and the Government, officials said, the Pakistani Interior Ministry will limit and monitor Khan’s telephone calls, visitors and activities.

US officials, who had objected to Khan’s release, expressed skepticism on Sunday about the new arrangement, which they said had been reported to them by the Pakistani Government. “We’re very concerned,” a US official said. Pakistan has “given us some initial commitments but we’re going to be following (the situation) very closely. The important thing is that they know we are very serious about this individual.”

Stung by growing international outcry questioning the release of A Q Khan, the Pakistani Government has said it is considering to file a fresh appeal against a court’s order declaring him a “free citizen”.

“The Government reserves the right to file an appeal against the High Court’s decision,” Foreign Minister Shah Mahmood Qureshi said on Sunday. Qureshi said the release of Khan from house arrest was due to the High Court’s order and not an “executive decision”. Qureshi had earlier said that Pakistan had “taken all measures” to ensure that Khan would be unable to resume the spread of nuclear secrets. “The proof is in the pudding,” said the US official, who added that US would be watching to determine whether the new restrictions were real.