Pakistan opposition leader Benazir Bhutto, who was placed under house arrest Friday after a tense standoff with police, was free to leave, government officials told FOX News.

Pakistan's police earlier had uncoiled barbed wire in front of her Islamabad villa and reportedly rounded up thousands of her supporters to block a mass protest against President Gen. Pervez Musharraf's emergency rule.

• FOX News Exclusive: Greta Van Susteren Speaks With Bhutto

Bhutto twice tried to leave in her car, telling police: "Do not raise hands on women. You are Muslims. This is un-Islamic." They responded by blocking her way with an armored vehicle.

• Click here to view photos.

The White House said Bhutto's release was "crucial for Pakistan's future that moderate political forces work together to bring Pakistan back on the path to democracy."

• Few Legal Restrictions Exist on U.S. Aide to Pakistan, Officials Say

Critics say Musharraf — who seized power in a 1999 coup — declared the emergency and ousted independent-minded judges to maintain his own grip on power. The moves came days before the Supreme Court was expected to rule on whether his recent re-election as president was legal.

"We remain concerned about the continued state of emergency and curtailment of basic freedoms, and urge Pakistani authorities to quickly return to constitutional order and democratic norms," Gordon Johndroe, a spokesman for the National Security Council, said in a statement.

Bhutto, a former prime minister, had planned to defy a ban on public gatherings and address a rally in nearby Rawalpindi, where police used tear gas and batons to chase off hundreds of supporters who staged wildcat protests and hurled stones. More than 100 were arrested.

Deputy Information Minister Tariq Azim said there was a restraining order against Bhutto, telling her to stay at her Islamabad home and not proceed to Rawalpindi because of the security threat. The city mayor said they had received reports that homicide bombers might attack the rally.

Friday's moves were expected to further sour relations between Bhutto and Musharraf and hurt prospects of the two pro-Western leaders forming a post-election alliance against religious extremism.

In an interview Friday with FOX News' Greta Van Susteren, Bhutto expressed concern for the pro-democratic movement in Pakistan.

"We worked out a road map after months of careful talks and I was quite hopeful," she said. "It was a big shock to me when he suspended the constitution."

Click here to listen to Part 1 of the interview.

Bhutto said she doesn't talk with Musharraf as much as she used to.

"We used to speak in the past, but now that he suspended the constitution, I thought it would give the wrong signal that I was somehow supporting the move toward the suspension of our constitution."

Bhutto said that while she was under house arrest, the police were allowing some people in but were being selective.

"Three women parliamentarians tried to come in this morning and they were arrested," Bhutto said. "They pick and choose who they want to let in."

Click here to listen to Part 2 of the interview.

Bhutto said lawyers who support the pro-democratic movement are afraid they are going to be out of jobs and journalists are being arrested for fighting for their right to report on the situation.

Her decision to join in anti-government protests against Musharraf is another blow to the military leader, whose popularity has plummeted this year amid growing resentment of military rule and failure by his government to curb increasing violence by Islamic militants.

Musharraf said the declaration of emergency last Saturday was needed to put an end to political instability and to fight Taliban and Al Qaeda-linked militants.

But most of the thousands of people rounded up countrywide have been moderates — lawyers and activists from secular opposition parties. Police have used batons and tear gas to squash attempts by lawyers to protest. Hundreds of students have also staged demonstrations on university campuses.

In the northwestern city of Peshawar, police used batons and tear gas to disperse about 300 Bhutto supporters as they gathered to depart for Rawalpindi. About 25 were arrested.

"We were peaceful, and this police action was totally without any reason," said Arbab Alimgir, a local leader of Bhutto's Pakistan People's Party.

There was confusion among Bhutto's aides about whether she still planned to go to Rawalpindi, where hundreds of riot police stood guard while other security personnel patrolled on motorcycles, horseback and in armored vehicles.

Police were also on the lookout for potential homicide bombers, who the city's police chief, Saud Aziz, warned Thursday were preparing a repeat of last month's bombing of Bhutto's jubilant homecoming procession in the southern city of Karachi after eight years of exile. She escaped unharmed, but more than 145 people died in the attack, blamed on Islamic militants.

Rawalpindi has also been hit by a series of attacks, targeting the military.

Bhutto supporters said they would only be further emboldened if their protest were blocked.

"We are going to besiege" Islamabad, said Abida Hussain, a former ambassador to the United States. "We will not go away. Our party activists have been mobilized to move out and take to the streets."

Authorities appeared determined to stop them. Bhutto's Pakistan People's Party, or PPP, claimed Friday that 5,000 of its supporters had been arrested in the last three days across the eastern province of Punjab.

"It is a massive crackdown on our party," said Raja Javed Ashraf, a PPP lawmaker.

The government offered no immediate public comment. But the security official said only 1,000 Bhutto supporters had been detained.

FOX News' Greta Van Susteren and The Associated Press contributed to this report.