Zardari has surprised many with his ability to concentrate power since his wife was assassinated in a December gun-and-bomb attack blamed on Taliban militants and he inherited her party's leadership.

Supporter of the ruling Pakistan People's Party lights fireworks as they celebrate the victory of Asif Ali Zardari, widower of slain Benazir Bhutto, in the country's presidential election in Islamabad September 6, 2008. [Agencies]

Former Prime Minister Nawaz Sharif's party abandoned the coalition and switched to the opposition last month. But Zardari quickly won support from smaller parties, suggesting he could provide some stability as the country faces soaring inflation, power shortages and widening trade and budget deficits.

Pro-Zardari lawmakers, some in tears, shouted "Long live Bhutto!" as the vote tallies came in. The couple's two jubilant but tearful daughters, one carrying a portrait of their late mother, smiled and hugged friends in the gallery of the National Assembly.

In the southern city of Karachi, capital of Zardari's home province, supporters waved his party's tricolor flags, beat drums and danced in the streets, chanting "Zardari is the strongest."

There was nothing festive about the mood in Peshawar, the main city of the Taliban-plagued northwest, which suffered the latest in a string of deadly suicide attacks.

Officials and witnesses said a pickup truck packed with explosives demolished a security checkpoint on the edge of the city Saturday, killing at least 30 people, including five police officers, and injuring dozens more.

No one immediately claimed responsibility. In recent weeks, however, the Pakistani Taliban have said they carried out a string of suicide bombings they called revenge for military offensives in the northwest region, which borders Afghanistan.

In more violence reported Saturday, 15 civilians and nine militants died when residents of the Swat valley foiled an attempt by insurgents to kidnap a pro-government elder, and then were attacked.

Pakistan has struggled to contain rising militancy in its borders, and the government has tried both peace talks and military operations.

It's an effort watched closely in the West, where officials worry that militants have safe havens in the northwest from which they plan attacks in neighboring Afghanistan, and could hatch another 9/11-style plot against North America or Europe.