Senator Lindsey Graham estimates US drone strikes have killed 4,700

Republican Senator Lindsey Graham said US drone strikes were a necessary tactical weapon.

A US senator estimates the United States has killed 4,700 people in drone strikes so far.

Speaking at the Easley Rotary Club on Tuesday, Republican Senator Lindsey Graham said the controversial drone program had been “very effective” and he opposed further judicial oversight.

“We've killed 4,700,” Graham was quoted by local media as saying.

“Sometimes you hit innocent people, and I hate that, but we're at war, and we've taken out some very senior members of Al Qaeda.

“I can't imagine in World War II for Roosevelt to have gone to a bunch of judges and said, 'I need your permission before we can attack the enemy.”

A number of media outlets reported this was the first time a US government official had offered a death toll for drone strikes. 

"Now this is the first time a US official has put a total number on it," Micah Zenko, a fellow at the Council on Foreign Relations, was quoted by Al Jazeera as saying.

But Graham’s spokesman told the Huffington Post that the senator was citing publicly available information from the London-based Bureau of Investigative Journalism.

The Pentagon is currently reviewing the drone program, which has been ramped up in recent years.

Spending on unmanned aircrafts rose from $284 million in 2000 to $4 billion in 2012.

The drone program has drawn criticism from both progressive Democrats and from Republicans concerned that it may result in too much power concentrated in the hands of the presidency.

More from GlobalPost: The Drone Age