VIDEO: A local Raqqa resident explains what happened on September 29.

New York-based rights group Human Rights Watch (HRW) said Tuesday that the Assad regime used a weapon known as a fuel-air bomb — also called a vacuum bomb — to target civilians at a school in Raqqa on September 29.

The bombs hit the Ibn Tufail Commercial Secondary School at around 8:05 a.m. on September 29. HRW has testimony from a Raqqa resident who said that he went to the school immediately after the attack, and saw 14 bodies, including some without limbs. HRW also spoke to a doctor from National Hospital in Raqq, who said he counted 12 bodies, mostly students, and the hospital treated 25 wounded.

HRW say that the regime attack against the school was likely a deliberate targeting of a civilian area.

Two other Raqqa residents, a lawyer and an opposition activist, told HRW that a regime fighter jet dropped bombs that struck the school’s courtyard, and that no armed personnel had been in teh vicinity of the school. There are no opposition administration offices or headquarters nearby the school, which had previously been used to provide shelter to a few hundred internal refugees from the Aleppo area.

The opposition activist said, “We heard the sound of a plane at exactly 8 a.m., and after a few seconds we heard the explosions. We went to the site after we identified it by the smoke rising from the scene. We got there after four to six minutes. Corpses were strewn on the ground and people were in a state of severe panic.”

The lawyer testified that, “Their body parts [of students aged 15-17] were scattered all over the place. They were just shreds, not full bodies, just pieces: the hand one place, the other body parts somewhere else. One head was severed from the body. One of them had the intestines coming out. Their books and notebooks were all over the place.”

According to HRW, whose researchers examined videos and photographs of the attack, blast wounds and flash burns visible on victims, as well as other visible evidence including body positions and few shrapnel wounds, indicates the use of fuel-air explosives. The burned skin and trauma wounds of the victims appear to be caused by flash burns and a blast wave, and not shrapnel wounds associated with conventional munitions. Some victims seemed to have been thrown against the wall of the courtyard, indicating that they had been forced there by the blast wind.

Fuel-air bombs, first used in Vietnam by the United States but later developed by the Soviet military for use in Afghanistan (and later by the Russian Federation military against Chechen militants), produce an explosion that is far more powerful and damaging than regular charges, particularly in densely populated areas. The bombs comprise a fuel container and two explosive charges, the first of which explodes and opens the fuel container at a particular height, dispersing the fuel so that it mixes with oxygen in the air. The fuel and oxygen cloud, which sinks and flows around structures, is then detonated by the second charge, producing a massive explosion. Fuel-air bombs are considered conventional weapons.

HRW have created this graphic of the explosions, showing the location of the impact craters.

Video of the aftermath of the September 29 attack, showing a crater created by one of the bombs:

Video explaining the use of the ODAB-500 fuel air bomb by Assad’s forces:

The Raqqa Media Center listed thirteen names of those killed in the September 29 bombing:

1. Ali Abu Hussein, 45-year-old janitor

2. Ahmed Khadr al-Faraj

3. Abdullah al-Nafa’a

4. Hassan al-Barjes

5. Rose al-Hassan al-Hussein

6. Ibtisam al-Hassoun al-Shuwaikh

7. Ali al-Shabib

8. Mohammed Rassoul al-Ibrahim

9.Ali Homaidy al-Ali al-Hussein

10.Mohammed Tareq al-Batran

11. Anwar al-Hassan al-Taher

12.Ammar al-Sheikh

13.Mahmoud Fady al-Awwad