By Staff Writer for ITV.

Victims of an American drone strike in Pakistan travelled to the US Congress today to explain the human cost of the controversial and secretive programme.

Rafiq Rahman travelled from his home in Waziristan to Washington to tell his story of how his 67-year-old mother was killed outright in a drone attack in which his three young children were injured.

Washington Correspondent Robert Moore reports.

Last week Amnesty International and Human Rights Watch released two scathing reports into the drone strike programme, saying the unlawful attacks on civilians could amount to war crimes.

The rights groups called on the US government to "come clean" about the number of unmanned aircraft attacks they are carrying out across north-west Pakistan.

The group said their research of 45 drone strikes over a year and a half found evidence that civilians were often targeted in attacks, and accused the US government of launching "rescue" attacks, were those assisting the injured were attacked in a second strike.

Human Rights Watch said their evaluations of six US drone strikes in Yemen found that two of the attacks killed civilians indiscriminately "in clear violations of the laws of war" and the others may have targeted people who were not legitimate targets, or caused disproportionate civilian deaths.

Amnesty International and Human Rights Watch are jointly calling on the US Congress to investigate the cases documented by their researchers, and disclosed any evidence of human rights violations or war crimes, and prosecute those responsible.