Davos: Pakistan's Prime Minister said on Saturday that there was "a trust deficit" between Islamabad and Washington as he criticised the resumption of US drone strikes on his country's tribal belt.

Speaking the day after over 100,000 people massed in Karachi to protest the strikes, Yousuf Raza Gilani said they only served to bolster militants.

"Drones are counter-productive. We have very ably isolated militants from the local tribes. When there are drone attacks that create sympathy for them again," Gilani told reporters at the Davos forum.

"It makes the job of the political leadership and the military very difficult. We have never allowed the drone attacks and we have always maintained that they are unacceptable, illegal and counterproductive."

Relations between the United States and Pakistan have deteriorated sharply over the last year, with Islamabad furious about the surprise deadly raid on al-Qaeda chief Osama bin Laden's hideout in Abbottabad last year.

The two sides have also been at loggerheads over a US air strike in November in which 24 Pakistani soldiers were killed.

The US halted drone strikes on Pakistan soil in the immediate aftermath of that strike but they have since resumed.

US officials say the northwestern tribal belt provides sanctuary to Taliban fighting in Afghanistan, al-Qaeda groups plotting attacks on the West, Pakistani Taliban who routinely bomb Pakistan and other foreign fighters.

In public, Pakistani leaders always insist they are against drone strikes, which are deeply unpopular in the country, but US officials insist that they privately cooperate with the programme.

Gilani said that Pakistan now wanted to agree new rules of engagement with the United States.

"The unilateral action taken in Abbottabad, that was not liked in any quarter ... We need assurances that such a unilateral action will not be repeated in the future. There is a trust deficit."

The Prime Minister said it was in both countries' interests to cooperate as partners and Pakistan had paid a high price at the hands of militant groups.

"We want to work together and we are fighting against militants and terrorists. We have paid a huge price for that."

Insurgents largely based in the tribal border lands have carried out bomb and gun attacks killing nearly 4,800 people across Pakistan since July 2007.

Pakistan has battled a homegrown insurgency for years, with more than 3,000 soldiers killed in the battle against militancy.