ISLAMABAD, Pakistan – A suspected suicide bomber killed at least 27 people and wounded 40 at an opposition rally Saturday in insurgency-wracked northwest Pakistan as police in Islamabad clashed with hundreds of lawyers and other protesters demanding the resignation of President Pervez Musharraf.

The widower of slain former prime minister Benazir Bhutto, meanwhile, kicked off the opposition Pakistan People’s Party campaign for Feb. 18 national elections with a speech to some 100,000 jubilant supporters.

“She is alive, Bibi, she is alive,” declared Asif Ali Zardari, using the nickname of his late wife, who died in a gun-and-suicide bomb attack on Dec. 27. “Her whole life was for you. My whole life is for you. My children’s lives are for you.”

It was by far the largest gathering of what has been a lackluster campaign, where fear of terror attacks has held back both candidates and crowds.

Friday’s violence bore out fears that political turmoil is likely to worsen in the run-up to the polls. Musharraf’s government responded by promising to step up security for candidates.

Amid the unrest, Adm. Michael Mullen, the chairman of the Joint Chiefs of Staff, met with Musharraf and top Pakistani military leaders to discuss a possible expansion of limited U.S. counter-insurgency training of Pakistani security forces.

The bombing Saturday occurred in Charsadda, about 25 miles from the North West Frontier Province capital of Peshawar, ripping through a rally of hundreds of supporters of the Awami National Party.

At least 27 people died and 40 were injured, said NWFP Special Home Secretary Teepu Khan, a senior security official.

“It might have been a bomb placed under the podium, but it looks like a suicide attack,” he told McClatchy Newspapers by telephone, adding that police had recovered a severed head believed to have belonged to the suspected bomber.

The ANP is a regional secular party representing Pashtuns, the ethnic group that inhabits the Pakistan-Afghanistan border region.

Pashtuns dominate the Afghan Taliban and the recently formed Taliban Movement of Pakistan, whose leader has been accused of plotting Bhutto’s slaying.

The clashes in central Islamabad erupted when police moved to disperse a protest by some 500 lawyers, political activists and students demanding Musharraf’s resignation and the reinstatement of fired Chief Justice Iftikhar Chaudhry.

The protesters planned to march to Chaudhry’s home, where he and his family have been under house arrest since Musharraf sacked him and dozens of other jurists in November.

Witnesses said police suddenly opened fire with tear gas and water cannon, igniting clashes with the protesters.

“We will keep struggling,” vowed Athar Minawalla, Chaudhry’s’ lawyer, when he was reached on his cellular phone at a police station after he and about one dozen others were arrested.

The protest was called as part of a national movement for the reinstatement of Chaudhry and the other judges led by lawyers who are boycotting courts across the country of 165 million.

The purge of the judges was seen as a bid by Musharraf, who seized power in a 1999 coup, to pre-empt challenges to legally dubious constitutional changes he enacted to extend his presidential term while remaining army chief, a post he resigned in December.