An official in President Gen. Musharraf's office confirmed Sharif was deported but did not divulge his destination. Both officials spoke on condition of anonymity as they were not authorized to speak to media. There was no immediate formal confirmation from the government.

Pakistan's Dawn News TV and ARY TV networks also reported that Sharif's destination was Jeddah.

Sharif's deportation came despite a landmark Supreme Court ruling last month that the two-time former premier, whose elected government was ousted by Musharraf in a 1999 coup, had the right to return to Pakistan and that authorities should not obstruct him.

"It is a violation of the constitution, and it is a violation of the court order under which Nawaz Sharif was allowed to arrive and stay in Pakistan," Sadique ul-Farooq, a close aide to Sharif told The Associated Press.

As Sharif's supporters battled police blocking roads leading to Islamabad airport, black-uniformed commandos entered the Pakistan International Airlines jetliner soon after it landed and surrounded Sharif, an Associated Press reporter on board said.

Sharif later disembarked with several of his supporters and government security personnel and entered the airport building.

While the move apparently sidelines a powerful political enemy of the general, it is likely to deepen Musharraf's growing unpopularity and reinforce public perceptions that he is an authoritarian ruler ahead of presidential and legislative elections.

In recent days, Sharif's party says up to 2,000 of his supporters have been rounded up "” although security officials put the number at around 700.

Overnight, police put at least four prominent opposition politicians under house arrest, and on Monday blocked all roads into the airport using trucks, tractors and barbed wire. The show of strength appeared to curb what Sharif's party had predicted would be a massive welcome for the former premier.

But police still clashed with the hundreds of Sharif supporters who did turn out.

They fired tear gas and supporter threw rocks in at least two separate locations near Islamabad and also a bridge on main highway leading to the capital from Pakistan's northwest frontier. Several people were injured at each clash, AP reporters said.

"We wanted to get to the airport to welcome the person who has challenged the dictator," said Asif Ali, one of the Sharif supporters near Islamabad. "We were tear-gassed and baton-charged."

Former President Rafiq Tarar, a Sharif loyalist, said he was roughed up in one confrontation. He declared the government was "anti-Pakistan." Witnesses said Tarar was later arrested.

Shortly before leaving London, Sharif asked his brother Shahbaz Sharif to remain in Britain to lead the party in case something happened to him in Pakistan.

He said he expected Musharraf to invoke emergency powers to stop his supporters in Pakistan "” but that this only underscored the need for him to return and fight to restore full democracy and the power of the judiciary.

"We are not scared of anything "” prisons and jails we have gone through all that," Sharif said.

Musharraf, who has received billions of dollars in U.S. aid to help in the country's fight against al-Qaida, plans to seek a new five-year term in office by mid-October. He has seen his popularity shrink since his failed attempt to fire Chief Justice Iftikhar Mohammed Chaudhry earlier this year spurred calls for an end to military rule.

Another exiled former prime minister plotting a political comeback, Benazir Bhutto, has said she also plans to return to Pakistan. She is due to announce her return date on Sept. 14.