US Air Force pilots started refusing to drop bombs on Islamic State targets as civilians deaths mounted due to a top secret unit ordering questionable strikes, it has emerged.

The objections from pilots came as a cell that initiated attacks in Syria reportedly ignored protocols designed to protect civilians.

A clandestine team called “Talon Anvil” launched tens of thousands of bombs and missiles in Syria between 2014 and 2019, the New York Times reported. Its targets included IS positions, fighters, convoys and car bombs.

But the way it carried out its mission was said to have alarmed others in the military and the CIA.

Four officials who had dealings with the unit said they often went ahead with strikes without enough evidence, and used the justification of self-defence when it didn’t apply.

‘They made a lot of bad strikes’

A former Air Force intelligence officer who worked with Talon Anvil told the New York Times: “They were ruthlessly efficient and good at their jobs. But they also made a lot of bad strikes.”

Talon Anvil reportedly consisted of only a few dozen people and was highly classified. It never officially existed.

It initially operated from Erbil, Iraq and then out of a former cement factory and housing complex in northern Syria.

The cell worked around the clock in three shifts gathering intelligence from drone footage, electronic surveillance, and allies on the ground.