Pakistani opposition leader Imran Khan Thursday said that he would seek compensation for victims of a controversial US drone strike programme, vowing to take their cases to parliament and the courts.

Khan, whose Pakistan Tehreek-e-Insaf (PTI) party opposes drone attacks, was speaking at the launch of a report demanding compensation for drone victims, organised by the independent Foundation for Fundamental Rights and international legal aid charity Reprieve.

Drone attacks are meant to target militants but are controversial among rights groups because of the high reported numbers of civilian casualties and lack of transparency over targets.

Islamabad officially opposes US strikes in its territory, calling them a violation of its sovereignty, though leaked documents in the past have shown the two countries worked together on the campaign.

"PTI will raise this issue in parliament and also go to court to get compensation for the drone victims," Khan said.

Afghanistan's government gets compensation for the families of civilians killed in strikes, he said -- but Islamabad neither receives any from the US government and nor has any been offered to a single victim.

Clive Stafford Smith, the director of Reprieve, said that the US does not acknowledge the innocent civilians it has killed in drone strikes.

"This report reflects in stark terms the fact that we value Pakistani life at zero, a situation that is offensive and simply cannot continue. I therefore, call upon my own government to compensate those innocent people caught in America's cross-fire," he said.

Fahim Qureshi, 18, whose entire family was killed in a drone strike in 2009 in northwest Pakistan that left him critically wounded, said he still did not know why they had been targeted.

"There is a question in my heart, why did it happen to us? What did we do?" he said, adding that they had no links with militants.

According to the independent Britain-based Bureau of Investigative Journalism, since 2004 the CIA has carried out 421 drone strikes in northwestern Pakistan killing up to 3,989 people, as many as 965 of whom were civilians, including dozens of children.