Chief Justice Iftikhar Muhammad Chaudhry, whose removal by President Pervez Musharraf on March 9 sparked nationwide protests, is set to address lawyers and opposition party supporters in the southern city of Karachi on Saturday.

Tensions rose after pro-Musharraf parties said they would hold rival demonstrations at the same time, while unidentified gunmen fired shots at the house of one of Chaudhry's lawyers in Karachi on Thursday.

"We have detained over 100 people as part of preventive measures," Karachi police chief Azhar Farooqi told AFP. More people may be detained over the next 24 hours to maintain law and order, he said.

The Pakistan People's Party of exiled former premier Benazir Bhutto said 300 of its workers were seized, while Pakistan's main alliance of religious parties said more than 500 of its activists were detained.

"We have taken all possible security measures in view of the highly charged atmosphere and over 15,000 police and paramilitary rangers have been deployed," Sindh province interior secretary Brigadier Ghulam Muhammad Muhtaram told AFP.

"The situation is tense and we are holding negotiations with all parties in order to avoid clashes," he said.

Police acting on government orders removed camps on Thursday set up by both sides in volatile Karachi, which has a history of ethnic and religious violence.

The pro-government Muttahida Qaumi Movement (MQM), an ethnic party for people who have emigrated from India, said it was holding a counter-rally on Saturday because opposition parties were politicising the judge's suspension.

The chief justice and his supporters will hold their rally at Sindh High Court while the MQM will gather about one kilometre away, on the city's main boulevard.

Tens of thousands of people turned out to greet Chaudhry when he spoke last Saturday in the eastern city of Lahore, the country's political and legal heartland, a development that shook Musharraf's government.

Chaudhry's lawyer Munir Malik said Friday that an attack on his house by gunmen the previous day was "not an attempt on my life but an attempt on the movement for the independence of the judiciary."

He said the top judge had called him and "assured him of the support of the entire lawyer fraternity."