According to reports, the largest non-nuclear bomb was dropped on ISIS fighters on September 7. Activists on Twitter claimed to have seen the Aviation Thermobaric Bomb of Increased Power (ATBIP), also known as the “Father of All Bombs” (FOAB) in action as part of a “precision air strike” that is said to have killed “some 40 ISIS fighters.”

According to the Daily Mail, the unconfirmed reports state that the FOAB was used near the Syrian city of Deir ez-Zor.

The strike occurred on the same day that the Russian Defense Ministry asserted several top ISIS commanders were killed.

In a Facebook post, the Russian Defense Ministry stated, “As a result of a precision air strike of the Russian air forces in the vicinity of Deir Ezzor city, a command post, communication center and some 40 ISIS fighters have been killed.”

Among the dead are said to be Gulmurod Khalimov, the US-trained “minister of war” with a $3 million bounty on his head as well as Abu-Muhammad al-Shimali, a high-profile commander.

At this time, the Russian Defense Ministry has not confirmed the FOAB was used during the strike.

Limited official footage of the FOAB is available, though the weapon is said to produce a cloud of flammable gas over the target prior to detonation, creating a pressure wave that can demolish hidden bunkers and vaporize anyone in the blast site.

After first testing the munition in 2007, Russian military sources stated the FOAB was “comparable to nuclear weapons.”

A FOAB uses aluminum powder and ethylene oxide, released as a cloud before detonation, to achieve a blast that is the equivalent of around 44 tons of TNT. It is said to weigh more than 14,000 pounds.

The name “Father of All Bombs” was chosen in an effort to demonstrate supremacy over the American-made “Mother of All Bombs.”

The FOAB is in the same class as the “Mother of All Bombs,” a weapon that was used by American forces in Afghanistan to destroy a network of ISIS tunnels in the Nangarhar province.

After the weapon detonated approximately six feet above the ground, the crater left by the blast was said to be more than 1,000 feet wide.