Hundreds of mourners wept Sunday as villagers buried victims of a horrific homicide bombing at a Pakistan election rally, an attack that killed 27 people and stoked fears about security ahead of next week's crucial parliamentary election.

The blast Saturday devastated a hall where about 200 people had gathered in the town of Charsadda, in the turbulent North West Frontier province where Islamic extremists have been battling government forces.

The rally was organized by the Awami National Party, a secular organization that competes against Islamist parties for support among the ethnic Pashtun community.

The party secretary-general, Mohammed Adeel, told reporters Sunday that 27 people died and 50 were injured in the blast.

"The entire village is grieving," said Tariq Khan, who attended a funeral for three men from Nahqi village who died in the blast. "We do not understand why such a big attack happened."

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He said the party had promoted peace in the North West Frontier area.

No group claimed responsibility but suspicion fell on Islamic extremists linked to the Taliban and Al Qaeda. Police recovered what they believe was the head of the bomber and planned DNA tests to try to establish his identity.

The suicide attack underscored the deep tensions in Pakistan as the nation heads toward Feb. 18 elections, which are meant to restore democracy after eight years of military rule.

But campaigning has been overshadowed by the Dec. 27 assassination of opposition leader Benazir Bhutto, which U.S. and Pakistani officials blame on Islamic militants.

Concern is mounting about the rise in violence in the volatile border area, where American officials believe Al Qaeda and the Afghan Taliban are regrouping after being driven out of Afghanistan.

The chairman of the U.S. Joint Chiefs of Staff, Adm. Mike Mullen, conferred Sunday in Peshawar with Pakistani military commanders running the battle against the extremists. He met a day earlier with Pakistan's President Pervez Musharraf and army generals to discuss the situation along the frontier.

Mullen, who left for the U.S. after the Peshawar meetings, told reporters in Pakistan's capital, Islamabad, that the recent increase in suicide attacks showed that "certainly the threat is going up."

The Taliban and Al Qaeda "have found safe havens here and it's in those safe havens that we are now very focused," he said. "It's a very deadly, lethal enemy that will not cease and that is why we have to work it very hard together."

U.S. officials hope the upcoming elections will help calm political passions, which have been sharpening since last March when Musharraf sought to rein in the country's independent judiciary. That move led to a sharp drop in support for Musharraf among urban professionals and other moderate groups within Pakistani society.

According to opinion poll results released during the weekend, 70 percent of Pakistanis want Musharraf to quit immediately.

The survey, conducted last month for the U.S.-based Terror Free Tomorrow organization, put support for Bhutto's party at 36.7 percent -- ahead of that of another former premier, Nawaz Sharif, and the ruling pro-Musharraf party, which trailed in third.

It also found that Al Qaeda chief Usama bin Laden's approval rating had dropped to 24 percent, compared to 46 percent during a similar survey in August.

Terror Free Tomorrow says it seeks to reduce support for international terrorism. Its bipartisan advisory board includes likely Republican presidential nominee Sen. John McCain. It said the survey, based on interviews with 1,157 people across Pakistan from Jan. 19-29, had a margin of error of plus or minus 3 percentage points

The ongoing violence has put a damper on political activity, especially in the northwest.

Candidates have shied away from large outdoor rallies in favor of small gatherings inside homes or high-walled compounds. Saturday's bombing showed that even those tightly controlled gatherings are unsafe.

Nevertheless, about 100,000 people gathered Saturday in a sports stadium in the southern city of Thatta as Bhutto's Pakistan People's Party resumed its election campaigning, which was suspended for the traditional 40 days of mourning after her death.

In an emotional speech, Bhutto's husband, Asif Ali Zardari, vowed to carry on his slain wife's mission "to save Pakistan."

Zardari claimed his wife was killed by an establishment that she wanted to change.

"That is why they were against us," Zardari said. "If they try to stop me, I will destroy them and I hope you people will support me."

The government has rejected allegations that intelligence agents or members of the ruling party allied to Musharraf plotted to kill Bhutto.