Pakistani police placed opposition leader Benazir Bhutto under house arrest Friday, uncoiling barbed wire in front of her Islamabad villa, and reportedly rounded up thousands of her supporters to block a mass protest against emergency rule. 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. The 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. Dozens were arrested. Further afield, a suicide bombing at the home of a government minister in the northwestern city of Peshawar killed four people. Minister for Political Affairs Amir Muqam was unhurt. The attack underscored the threat posed by religious extremists in this Islamic nation that President Gen. Pervez Musharraf and Bhutto are sparring over. It was cited by Musharraf as the primary reason for imposing the state of emergency last Saturday. But most of the thousands of people rounded up countrywide since have been moderates - lawyers and activists from secular opposition parties, such as Bhutto's Pakistan People's Party. The mass detentions have fueled criticism that Musharraf - who seized power in a 1999 coup - declared the emergency to maintain his own grip on power. Friday's crackdown showed that Musharraf was not letting up on his political rivals, despite saying a day earlier that parliamentary elections would go ahead by mid-February, just a month later than originally planned. His announcement came after intense pressure from the United States, his chief international supporter. It also dimmed prospects that Bhutto and Musharraf would soon form an alliance against Islamic extremists that Washington has pushed for. Speaking to reporters by phone between her two attempts to escape her home, Bhutto said her supporters would "continue to fight for democracy and the rule of law." She also repeated demands that Musharraf step down as army chief by next week, when his presidential term expires. Bhutto's 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 Taliban and al-Qaida militants. Scores of police, some in riot gear, kept a wary eye on Bhutto's supporters outside her house, who repeatedly tried to remove barbed wire and steel and concrete barriers. At least 30 Bhutto supporters were arrested, including a woman who showed up with flowers. An old bearded man who showed up with a sharp machete and a goat he planned to sacrifice to bring Bhutto good luck was simply shooed away by police. There was confusion over whether authorities had served Bhutto with a formal detention order. Officials said they had, but Bhutto's aides said they had not received it - and would not accept it. An intelligence official, speaking on condition of anonymity because he was not authorized to speak to media, said Bhutto was ordered detained for 30 days, but the government did not confirm that. Bhutto twice tried to leave for Rawalpindi inside a white Landcruiser with tinted windows, surrounded by about 50 supporters, including several lawmakers. After being turned back a second time, her way blocked by an armored vehicle, she got out of her car and joined her supporters, who chanted "Go Musharraf Go!" She then delivered an address heard by reporters on the other side of the barricades. "I want to tell you to have courage because this battle is against dictatorship and it will be won by the people," she told her followers. Her supporters said they would only be further emboldened by Friday's clampdown. "We are going to besiege" Islamabad, said the 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. But security officials said only 1,100 had been detained. Interior Ministry spokesman Javed Iqbal Cheema said authorities had stopped the rally because suicide bombers had gathered in Rawalpindi and Islamabad. "The rally was stopped only and only because of our security concerns," he said on state-run Pakistan Television. Rawalpindi's mayor had earlier in the day warned of a "credible report" that six or seven bombers were preparing a repeat of last month's attack 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.