Opposition leader Benazir Bhutto, center, waves as she and her supporters are blocked by Pakistani police and a barbed wire blockade outside her home Friday in Islamabad, Pakistan.

Islamabad, Pakistan ? Pakistan quickly ended house arrest for opposition leader Benazir Bhutto on Friday as President Gen. Pervez Musharraf came under new U.S. pressure to end a crackdown that Washington fears is hurting the fight against Islamic extremism.

Earlier in the day, police put barbed wire around Bhutto’s house to keep her from speaking at a rally to protest Musharraf’s imposition of emergency rule, and security forces rounded up thousands of her supporters to block any mass demonstrations.

The action was a new blow to hopes the two U.S.-friendly leaders could form an alliance against militants – a rising threat underlined by a suicide bombing in northwest Pakistan that targeted the home of a Cabinet minister, who escaped without injury.

Bhutto twice tried to evade authorities in her car, telling police who surrounded her villa: “Do not raise hands on women. You are Muslims. This is un-Islamic.” Officers blocked the former prime minister’s way with an armored vehicle.

In Rawalpindi, the nearby garrison town where she had hoped to stage the rally, police fired tear gas at hundreds of Bhutto loyalists who staged protests and hurled stones. More than 100 were arrested.

The Bush administration called for the restrictions on Bhutto to be lifted, and Pakistan’s government said late Friday that she was again free to move about, although police barriers remained outside her house. Her supporters said she would try to leave this morning.

In Washington, where some lawmakers are calling for aid to Pakistan to be curtailed, U.S. officials again criticized Musharraf’s crackdown.

“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.

As Musharraf’s chief international backer, the Bush administration is deeply concerned about the deteriorating situation in Pakistan, a nuclear-armed nation of 160 million people that is on the front lines of the U.S.-led campaign against terrorist groups.

The suspension of the constitution last weekend has intensified the anger of moderate and secular Pakistanis who have become increasingly frustrated with military rule. At the same time, Islamic militants with ties to the Taliban and al-Qaida are stepping up violence, including suicide bombings and fighting in the northwest along the border with Afghanistan.

Musharraf cited the gains by extremists in the frontier region as one of the main reasons for his emergency decree, saying political unrest was undermining the fight against militants.

Despite the government’s attempt to squelch Pakistani news coverage of the unrest, some independent TV channels are finding ways to broadcast reports. Geo TV, for instance, transmits by satellite from a backup facility in the Persian Gulf and it streams video on the Internet.