A suicide bomber struck Saturday at an election rally in northwestern Pakistan, killing at least 25 people and wounding dozens, officials said.

The blast occurred inside a hall where some 200 people had gathered for the rally of a secular, ethnic Pastun group in the town of Charsadda in the turbulent North West Frontier province, where Islamic extremists operate.

Volunteers help a man injured in a suicide bombing to exit an ambulance at a local hospital in Peshawar, Pakistan, on Saturday. The bombing was the second to rattle the town of Charsadda in as many months.
(Mohammad Zubair/Associated Press)

"I think it was a suicide attack and very close to the stage," Interior Minister Hamid Nawaz said, adding that all party leaders were safe.

Afrasiab Khattak, the Awami National Party's provincial leader and a prominent human rights champion, who was addressing the rally said he was not hurt.

The violence underscored deep tensions in Pakistan as the country nears the Feb. 18 parliamentary elections, aimed at restoring democracy after eight years of military rule.

The election was postponed for six weeks following the Dec. 27 assassination of former prime minister and opposition leader Benazir Bhutto, whose death both U.S. and Pakistani officials blame on Islamic militants.

Two policemen were among the dead and several children were killed or injured at Saturday's suicide bombing, said police officer Mohammed Khan.

No group immediately claimed responsibility for the attack, but suspicion fell on Islamic militants with ties to the Taliban or al-Qaeda.

"It was an action by the ill-wishers of Pakistan who do not want the elections to take place," said Shamsul Mulk, chief minister of North West Frontier province.

Nawaz said the militants are threatening all political parties in the northwest. "They are against everyone," Nawaz told Dawn News TV.

Though candidates have shied away from large outdoor rallies following Bhutto's killing, Saturday's bombing showed that even smaller gatherings inside homes or compounds were unsafe.

Nevertheless, about 100,000 supporters of Bhutto's Pakistan Peoples Party came together Saturday at a sports stadium in the southern city of Thatta as the party resumed its election campaigning.

Campaigning was suspended for the traditional 40 days of mourning after her death.

In an emotional speech, Bhutto's husband Asif Ali Zardari asked the crowd to "give me strength so that we can serve the country." He vowed to carry on his slain wife's mission.

With files from the Associated Press