Bhutto, who herself was kept under house arrest for most of Friday, tried to approach former chief justice Iftikhar Chaudhry's home, where he is being detained, but police parked two trucks on the road to block her path.

After imposing emergency rule and suspending the constitution a week ago, citing a hostile judiciary and rising militancy, General Musharraf sacked most of the Supreme Court's judges and has since replaced them with more amenable ones.

"He is the chief justice, he is the real chief justice, " Bhutto blared over a megaphone, demanding they all be reinstated.

Bhutto will defy Musharraf and go ahead with a pro-democracy motorcade from Lahore to Islamabad next week, after police scotched a protest by her Pakistan People's Party in the garrison town of Rawalpindi adjoining Islamabad on Friday.

Police used batons and tear gas to break up small protests in several parts of the country, but demonstrations have been relatively small by Pakistani standards.

Pakistan's slide into political uncertainty has accelerated over the past week with military chief Musharraf 's imposition of emergency rule scaring foreign investors and spooking domestic markets. Thousands of Musharraf opponents have been arrested.

Bhutto, the Pakistani politician most able to mobilise masses, was due to meet foreign diplomats later in the day.

She briefly joined journalists protesting outside the offices of a television channel against a blackout on private news broadcasts. BBC and CNN are also off the air, though newspapers are still publishing freely.

Bhutto is due to head to Lahore today, and has said Musharraf can defuse the protest if he restores the constitution, removes his army uniform and calls elections by midJanuary.

Musharraf has said elections will be held by 15 February, about a month later than they were due.

He also said he would quit as army chief and be sworn in as a civilian president once new judges appointed to the Supreme Court struck down challenges against his re-election.

Officials say Musharraf will likely keep the emergency short.

"The emergency will end within a month or two. It all depends on the law and order situation, " said Attorney General Malik Abdul Qayyum.