Activists opposed to US drone strikes against Al-Qaeda suspects demanded Friday an end to the secrecy surrounding the attacks, saying the bombings have claimed numerous civilian lives.

"We are questioning the entire issue of a policy that is done under the shadows of secrecy without accountability," said Medea Benjamin, co-founder of the CodePink anti-war group.

"If indeed this is a program that is supposed to be designed for reaching high-level Al-Qaeda members who are about to kill us Americans, this program is very much off the mark," Benjamin told a news conference.

Benjamin was accompanied by Yemeni families whose relatives were killed in drone missile strikes, as well as Yemeni civil society advocates.

One member of the Yemeni delegation included Faisal bin Ali Jaber, who lost a brother-in-law and a 21-year-old nephew in a drone strike on August 19, 2012.

Jaber's brother-in-law had been an imam known for his opposition to Al-Qaeda, and his late nephew was a policeman, activists said.

"What we see as a result, is how counterproductive this policy is, how it has led to a growing anti-American sentiment," Benjamin said.

The drone operations have been approved by Yemen's president Abdrabuh Mansur Hadi but denounced by his own party as well as the National Dialogue, which gathers members of the country's civil society, according to Baraa Shiban, a member of the organization who also investigates drone attacks for a human rights group.

"The image that is created by the American government doesn't really help us at the National Dialogue, Shiban said.

The number of victims from the drone strikes in Yemen remains unclear and estimates vary widely.

According to the Washington-based New America Foundation, a think tank that has tried to closely track and vet the numbers, 93 strikes since 2002 have killed 684 to 891 people including between 64 and 66 civilians.

In Pakistan, 367 drone attacks since 2004 have killed 2,071 to 3,413 people, about one in ten of whom have been civilians.

Friday's news conference was part of a series of "Drone Summit" events organized by CodePink to urge President Barack Obama's administration to halt the drone strikes.

Dozens of protesters marched Friday in front of the White House, then headed towards the offices of General Atomics, the manufacturer of the Predator and Reaper unmanned aircraft used in the controversial strikes.

The Obama administration has defended the drone bombing campaign as an effective tool against Al-Qaeda-linked militants, but has promised to introduce stricter rules and oversight for the strikes, including shifting more of the operations from the CIA to the military to reduce secrecy.