ISLAMABAD: Top US envoy Richard Holbrooke praised Pakistan Sunday for military gains against Taliban insurgents, but his words were tempered by surging pre-election violence in neighbouring Afghanistan.

President Barack Obama's top troubleshooter for the Muslim neighbours said that Pakistan was "much better off" than a few months ago, when emboldened Islamist militants thrust to within 100 kilometres (60 miles) of the capital.

Pakistan's government now claims to have "eliminated" the Taliban from the northwest districts of Swat, Lower Dir and Buner in a punishing military offensive launched in late April after the rebels flouted a peace deal.

"We were very impressed with their success so far and we are glad to see the progress that has been made," Holbrooke said.

"We all know that the underlying problems are still to be dealt with," said the envoy, who arrived in Islamabad late Saturday.

"But we are much better off today as we appear to (have) one less very bad person around -- Baitullah Mehsud," he said, referring to the Pakistan Taliban chief reported killed in a US missile strike earlier this month.

It is Holbrooke's fifth trip to Pakistan since his appointment in January this year, as Obama's White House puts the country at the heart of its fight against Islamist extremists and vows to boost US aid and assistance.

On Sunday, Holbrooke met Pakistan's Foreign Minister Shah Mehmood Qureshi and the main opposition politician Nawaz Sharif. Talks with Qureshi focused on energy and economic cooperation, Holbrooke said.

He had been due to travel to Swat valley, but heavy rainfall forced the trip to be postponed, a US embassy official said.

Holbrooke is also scheduled to meet President Asif Ali Zardari, Prime Minister Yousuf Raza Gilani and army chief General Ashfaq Kayani during his three-day stint in Pakistan, before travelling to Afghanistan.

His trip comes ahead of Thursday's presidential and provincial elections in Afghanistan, seen as a key test of NATO- and US-driven efforts to bring peace and democracy to the war-scarred nation.

But spiraling attacks by the Taliban and other extremist groups have raised fears that Afghans will be afraid to turn out to vote, throwing into question the legitimacy of the nation's second presidential election.

On Saturday, a suicide car bomb exploded outside the NATO military headquarters in Kabul, killing seven Afghans.

The Taliban also threatened for the first time Sunday to directly attack polling stations, and a militant spokesman said the group would accelerate its bloody campaign of violence on the eve and day of elections.

Pakistan, meanwhile, has been weighing a fresh offensive against the Taliban in the northwest tribal belt bordering Afghanistan, believed to be a bolt hole for Al-Qaeda rebels who Washington says are plotting attacks on the West.

In an apparent blow for the militants, Pakistan Taliban chief Mehsud was this month reported killed in a US drone missile strike in South Waziristan, although both countries have stopped short of confirming his death.

Analysts have said US pressure will now mount on Pakistan to take advantage of the drone attacks and step up its fight against the Taliban in the lawless tribal terrain, where militants slip across the porous border into Afghanistan.

Holbrooke, however, said that the US would not interfere.

"On the question of the Pakistan forces and how they are going to be used and when and if they will go into other areas, that is a decision for the Pakistan government to make and for them to make alone," he said.

Qureshi told reporters that the umbrella organisation Tehreek-e-Taliban Pakistan was "in disarray" after the reported death of Mehsud -- claims previously denied by the Taliban, who say the warlord is still alive.

"They have not yet been able to nominate someone to succeed him. That shows a lot of infighting within the ranks... we will go to every area to clear our territory of terrorists," Qureshi said in Islamabad.

Pakistan says the northwest offensive killed more than 1,800 militants and 166 security personnel -- death tolls impossible to verify independently.