By Al Jazeera Staff for Al Jazeera America. 

U.S. lawmakers heard testimony Tuesday morning from survivors of an alleged drone strike for the first time in history, with three Pakistani citizens appearing before Congress to describe an attack that killed their matriarch in Pakistan last year.

Schoolteacher Rafiq ur Rehman and his two children — 9-year-old daughter Nabila and 13-year-old son Zubair — traveled on the invitation of Rep. Alan Grayson, D-Fla., to Washington, where they shared their accounts of the alleged drone attack that killed Rehman's mother, Momina Bibi, and injured two children in the remote tribal region of North Waziristan last October.

The Rehmans, shocked by the attack, which appeared to target Bibi, a 67-year-old midwife, wants answers from Congress. Encouraged by prominent anti-drone activist and Rehman’s lawyer, Shahzad Akbar, they earned an invitation from Grayson to appear at the hearing.

Originally slated for last month, the hearing had to be postponed because of visa issues that prevented Akbar, who has spearheaded cases on behalf of dozens of other alleged drone victims, from entering the U.S.

A petition on MoveOn.org, authored by Rehman, asking the State Department to grant Akbar a visa garnered nearly 5,000 signatures, and the campaign was ultimately successful.

The U.S. government has not formally acknowledged responsibility for the October 2012 strike — nor has it hinted at an explanation for why an elderly woman was killed — but State Department officials have referred reporters to a press briefing from deputy spokesperson Marie Harf last week.

“There’s a process that goes into how these operations are chosen, and as part of that process, we take every effort to limit these casualties,” Harf said on Oct. 22.

Mustafa Qadri, an Amnesty International researcher who has investigated the incident, says the attack was consistent with a U.S. drone strikes and that it is unlikely that any legitimate targets were present when Bibi was killed.

The family says Bibi was picking vegetables when she was struck. Zubair required a series of expensive operations to remove shrapnel from his leg.

Rehman told The Guardian ahead of the hearing that he wanted to use the it as a platform to convey, through a translator, the horrors of drone strikes to lawmakers and the American people.

“I want them to know the drones are having an impact on our lives,” he told The Guardian. “It’s hitting our elders. It took my mom. It’s affected my children, and we haven't done anything wrong.”

Filmmaker Robert Greenwald also appeared at the Tuesday hearing, where a preview of his upcoming documentary on drone strikes, “Unmanned,” will be screened.

Pakistanis have long called for an end to U.S. drone strikes in their country, and on Wednesday Prime Minister Nawaz Sharif said he emphasized “the need for an end to these strikes” during a meeting with President Barack Obama at the White House.

On Thursday, however, the Washington Post revealed leaked CIA and official Pakistani documents indicating that Pakistan’s government were complicit in attacks.

Amnesty International and Human Rights Watch both released reports this month suggesting that U.S. drone policy may violate international law.