Islamabad, Pakistan - The sweeping security crackdown by Gen. Pervez Musharraf that thwarted a protest rally against his emergency decree by the opposition leader Benazir Bhutto left the two adversaries locked in a standoff on Friday.

On the surface, the show of force by the government, which deployed thousands of police officers and other security personnel and confined Ms. Bhutto to her house here for most of the day, appeared to leave the rivals further from a power-sharing deal.

But events did not exclude the possibility that back-channel talks were proceeding, and Bush administration officials said they held out hope that the two leaders could still defuse the crisis that began when General Musharraf declared de facto martial law six days ago.

Some 8,500 police officers locked down Rawalpindi, the planned site of the protest, so completely that only small groups of protesters made it into the city. Dump trucks, tractor-trailers and carts blocked all streets leading to the central square. Riot police officers on motorcycles threatened to beat groups of pedestrians who failed to disperse on command.

And Ms. Bhutto was virtually kept hostage in her compound, behind rings of barbed wire.

By the end of the day, chaotic as it was, the standoff allowed both Ms. Bhutto and General Musharraf a face-saving way, whether impromptu or choreographed, to avoid potentially bloody clashes on the streets.

At one point Ms. Bhutto tried to show her determination to go to Rawalpindi, the garrison town adjacent to the capital. She got into her white four-wheel-drive to leave, but a police bus and a personnel carrier blocked her way.

Later in the afternoon, in what appeared to be a stage-managed move agreed on with the government, Ms. Bhutto emerged at the barricades and made a 20-minute speech that was broadcast on official Pakistani television.

And she rejected the announcement made by General Musharraf on Thursday that he would hold parliamentary elections before Feb. 15, saying that it fell short of her demands to relinquish his role as head of the army and end emergency rule.

By Friday evening, a government spokesman, Tariq Azim Khan, said Ms. Bhutto was free to leave her home. A restraining order had been placed on her for the day, he said, to prevent her from attending the rally, which had been banned under the emergency decree.

The spokesman said Ms. Bhutto had been confined because the government had had warnings of potential attacks against her in Rawalpindi, and did not want a repeat of the suicide attack against her last month, when Ms. Bhutto returned to Pakistan after living eight years abroad to avoid prosecution on corruption charges.

After that attack, in Karachi, Ms. Bhutto blamed the government for not paying proper attention to her security. She has since accused it of using the threats against her to justify its crackdown on any demonstration by the opposition.

That crackdown has swept up about 2,500 people from various opposition groups over the last several days, according to Western diplomats. Officials of Ms. Bhutto's party put the number far higher, at as many as 5,000 party workers nationwide.

On Friday, the police blanketed several square miles of Rawalpindi and shut down the city center to prevent workers and supporters of her Pakistan Peoples Party from reaching Liaquat Park, the site of the planned rally.

Protesters, fearing arrest, lurked in the old city's warren of alleys. Seething residents said they had never seen so many police officers in the city.

"I'm scared," said Imran Ali, a 25-year-old medical company worker. "I'm not happy to see my country very deeply troubled."

Party workers from Rawalpindi and other major cities said they waited for orders from the party's central command about when to take on the police. Eventually, small groups of several dozen protesters began challenging the police on their own.

By late afternoon, orders arrived for protesters to carry out small attacks on the police, protesters and party workers said. As the sun set, the police began to leave the city and party workers dispersed. Workers said they did not know why Ms. Bhutto never ordered them to carry out larger attacks.

The police said 108 protesters were arrested across the city.

In Islamabad, the capital, Ms. Bhutto was surrounded by three layers of police lines, barbed wire and concrete barriers, and an armored personnel carrier blocked the entrance to her house at the end of a tree-lined cul-de-sac.

Senior party members, many of them well dressed and in designer sunglasses, were ushered past the barricades and into her home.

About 20 party workers, most of them in the lower ranks, were arrested outside her house during the day. Some of those arrested shouted "Prime Minister Benazir," a reference to Ms. Bhutto's desire to be prime minister a third time, as they were driven away in blue police vans, their fingers forming V-for-victory signs through the bars.

How much of the day's events were the result of strategies worked out in advance to avoid tipping the country deeper into crisis was difficult to divine.

But with the mass arrests and near complete lockdown of Rawalpindi, the government was able to demonstrate its resolve, and by getting in her car and starting out the side entrance of her house where she was blocked, Ms. Bhutto was, too.

In her rejection of General Musharraf's concessions, Ms. Bhutto was undoubtedly walking a fine line between the competing constituencies she needs to appease. She had to balance the demands of her backers in Washington, who would like to see her and the general share power, and the feeling on the streets of Pakistan, where the appearance of backroom deal-making between Ms. Bhutto and the general has diminished the standing of both leaders.

Even amid the tensions, Western diplomats said Ms. Bhutto and General Musharraf were continuing to negotiate the power-sharing deal that was brokered by the United States and Britain as a way of returning Pakistan to some form of democratic rule.

Those negotiations could be thrown into jeopardy if tensions from Friday's standoff boiled over, said Hasan Askari-Rizvi, a political and military analyst in Lahore who also lectures in Washington at the School of Advanced International Studies of Johns Hopkins University.

There was still no sign, for instance, that General Musharraf would renounce his military position, Mr. Rizvi said. "If Musharraf can contain these protests for three days, fine," he said. "But if the protests spread to cities and persist for a week, then Musharraf will have problems."

In an indication of how Ms. Bhutto appeared to have preserved her freedom of movement after Friday's events, a senior aide said she planned to go ahead with a diplomatic reception at the Senate building on Sunday night.

Meanwhile, the general's emergency rule, while having helped plunge the country into turmoil, failed to counter the threat from extremists. A suicide bombing in Peshawar struck the home of a federal minister and killed four people on Friday afternoon, the first such attack since the general's decree.

The federal minister for political affairs, Amir Muqam, was meeting with colleagues at his home in the well-heeled quarter of Hayatabad when the bomber tried to crash into his house.