Karachi, Pakistan ? Authorities marshaled 15,000 security forces Friday in Pakistan’s largest city, fearing clashes during rival protests by opponents of President Gen. Pervez Musharraf and a pro-government party with a history of violence.

Government opponents hope to have their biggest demonstration yet today against Musharraf’s decision to suspend the head of the Supreme Court two months ago, a move that has plunged Pakistan into deepening political turmoil.

The Mutahida Qami Movement, a pro-government party with a support base in Karachi, has announced it will have a counter-rally less than a mile away. In the 1990s, scores of MQM activists were arrested for allegedly kidnapping dozens of their rivals and attacking security forces. Party activists are still heavily armed, but critics say they enjoy impunity as part of Musharraf’s government.

“If something happens to the chief justice, or any of his supporters in Karachi or elsewhere, the government alone would be responsible for it,” said Farhatullah Babar, spokesman for the main opposition Pakistan Peoples Party.

Opponents accuse Musharraf of trying to sideline the independent-minded Chief Justice Iftikhar Mohammed Chaudhry in case of legal challenges to his plan to seek a new five-year term in elections this fall.

Musharraf, a key U.S. ally who took power in a bloodless 1999 coup, denies Chaudhry’s suspension was politically motivated, saying there was serious evidence that the judge abused his position.