Protesters shouted slogan against the release of CIA contractor Raymond Davis at rallies after prayer [AFP]

Hundreds of Pakistanis have marched against the government in protest over the release of a CIA contractor who had been held for murder.

Protesters in Islamabad led by the Tehreek-e-Insaaf (Movement for Justice) party of cricketer-turned-politician Imran Khan marched from Islamabad's Red Mosque after Friday prayers, chanting anti-government and anti-US slogans.

Outrage was further heightened by a US air strike in North Waziristan on Thursday, killing at least 38 people.

"All of us Pakistanis have to get together and decide that in the future if ever the life of any Pakistani is taken, 180 million Pakistanis will come out onto the streets," Khan said.

The protesters chanted "Friends of the US are traitors" and "Down with America".

The march came two days after Raymond Davis was released after the families of the two men he admitted to killing were given so-called "blood money" and the case was dropped.

US-Pakistan relations

Davis, who had earlier admitted to the killings but said he was acting in "self-defence", was indicted for the murders on Wednesday. But Rana Sanaullah, the Punjab law minister, said he was immediately pardoned by the families of the victims in exchange for compensation.

Washington, however, denies any money was ever paid.

Davis' detention in Pakistan had strained ties between Washington and Islamabad.

Kamal Hyder, Al Jazeera's correspondent in Islamabad, said: "Paying money is one thing, but there has been denial from the US. The important thing is how the two [US and Pakistan] patch up their relationship."

Our correspondent also reported that tribal leaders have declared revenge on the US after Thursday's strike.

"It must not be forgotten that the tribes never leave without taking revenge," he said.

"Whenever someone is killed there will invariably be revenge - something that the Americans know very well, they have been operating in Afghanistan after all. Now the tribes are saying they are going to hit the Americans on both sides of the border, whenever, wherever possibly."

Source: Al Jazeera and agencies