Pakistan's military ruler has amended a law to give army courts sweeping powers to try civilians on charges ranging from treason to inciting public unrest, officials said Sunday, as the country's opposition leader prepared to stage a 185-mile protest march in defiance of a ban.

The moves came one week after President Gen. Pervez Musharraf said he was imposing a state of emergency to help fight Islamic militancy. But the main targets of his crackdown have been his most outspoken critics, including the increasingly independent judiciary and media.

The army chief — under pressure from the United States and other Western allies to return to the path of democracy — won praise for agreeing Saturday to lift the emergency within weeks and hold elections by Feb. 15, just one month later than originally scheduled.

U.S. President George W. Bush described the promises as "positive," throwing Washington's support firmly behind the embattled Pakistani leader, whom he has in the past described as a good friend.

But a decision to amend the Pakistan Army Act — confirmed by Attorney General Malik Mohammed Qayyum on Sunday — is likely to raise fresh concerns. It would allow military courts to try people accused of treason, sedition, or "giving statements conducive to public mischief."

In theory, that could include Bhutto, who said she would defy Musharraf's ban on public gatherings and lead supporters on a march from the eastern city of Lahore to the capital Islamabad on Tuesday.

"When the masses combine, the sound of their steps will suppress the sound of military boots," Bhutto, a former prime minister, told hundreds of protesters Saturday, almost immediately after she was freed from 24 hours of house arrest.

Addressing supporters through a loudspeaker, she said Taliban and al-Qaida-linked militants were gaining ground in the country's turbulent northwest. She also said Musharraf's military-led government was about to crumble.

"This government is standing on its last foot," the former prime minister said, as dozens of supporters scuffled briefly with police. "This government is going to go."

Thousands of people have been arrested, TV news stations taken off air, and judges removed from office since Musharraf imposed his state of emergency.

Musharraf was to hold a press conference with foreign journalists later Sunday. Three reporters from Britain's Daily Telegraph meanwhile left Pakistan on Sunday after being expelled in protest of a commentary in their newspaper that used an expletive in reference to Musharraf.

The United States considers Musharraf a bulwark in its so-called war on terrorism, but some U.S. officials have expressed concern that Pakistan's political crisis would actually distract its efforts against a militant threat that has spread from the Afghan border region to the capital and beyond.

Bush sidestepped a question on that issue, saying he has confidence in the commitment of Pakistan's leadership to stick with the U.S. in its global fight against extremists. "One country we need cooperation from is Pakistan," he told reporters in his home state of Texas.

Bhutto's jubilant homecoming procession last month following eight years in exile was marred by twin suicide bombings. She escaped unharmed, but more than 140 people died in the attack, widely blamed on Islamic militants.

Many critics say the main goal of Musharraf's emergency was to pre-empt a Supreme Court ruling on the legality of his victory in a presidential election last month. Under the constitution, public servants cannot run for office.

Qayyum, the attorney general, said the court — now purged of its more independent justices — would swear in more judges in the next two or three days, bringing it up to the strength required to restart hearings in the case.

Musharraf says he will quit his post as army chief and rule as a civilian once the court has confirmed his re-election, but set no date for that step.