ISLAMABAD: President-elect Asif Ali Zardari faced immediate pressure on Sunday to tackle an upsurge in militant violence, as the toll from a suicide blast in the country's troubled northwest reached 35.

Zardari, who won a two-thirds majority in a secret ballot among lawmakers on Saturday, was expected to be sworn in as leader of the world's only nuclear-armed Islamic state and frontline US "war on terror" ally on Monday. The militant threat was underscored in Peshawar during voting on Saturday, when a suicide car-bomber rammed a police checkpost.

The unrest is seen as a backlash by militants angry at the support given to the United States by former president Pervez Musharraf, whose August 18 resignation triggered Saturday's election.

“I will work to defeat the domestic Taliban insurgency and to ensure that Pakistani territory is not used to launch terrorist attacks on our neighbours or on Nato forces in Afghanistan,” Zardari said in an editorial before his win.

Zardari is also facing pressure from the opposition to reverse controversial changes to the Constitution made by Musharraf, which give him the right to dismiss parliament, as well as make key military and judicial appointments.

"Zardari's first test is that as president he facilitates the transfer of Musharraf's powers to parliament," said Ahsan Iqbal, a former minister and senior figure in the party led by two-time former premier Nawaz Sharif. Sharif's allies have already demanded that Zardari resign as co-chairman of the Pakistan People's Party (PPP) in the wake of his victory.

"We want the president to be apolitical -- that has been the tradition and we hope this tradition is kept," Iqbal said.

Pakistan's economy is also in trouble with rampant inflation and a plunging stock market that has lost around 40 per cent of its value since January, in a country already reliant on foreign aid.

Zardari, 53, defeated retired chief justice Saeeduzzaman Siddiqui, who was backed by Sharif, and Mushahid Hussain, a close aide of Musharraf, in Saturday's election. He will become the 14th president in Pakistan's short but turbulent history, and was likely to be sworn in on Monday, a top party official said on Monday.