BEIRUT: Twenty members of the Islamic State of Iraq and Greater Syria (ISIS) were killed in Syrian air force raids Wednesday morning against the jihadists' bastion in Raqqa, an activist group said.
"At least 20 members of ISIS were killed and others were injured in air strikes... targeting an ISIS training base in Raqqa," said the Syrian Observatory for Human Rights.
The strikes also destroyed 14 of ISIS' military vehicles, the Observatory added.
On June 29, ISIS declared the establishment of a "caliphate", referring to an Islamic system of rule that was abolished nearly 100 years ago.
Its jihadists are firmly in control of Raqqa, their stronghold, and have secured large swath of territory in eastern Syria and in neighboring Iraq.
While some in the Syrian opposition initially welcomed ISIS among their ranks, viewing it as a potential ally, its abuses and quest for control turned the rebels against them.
Rebels have been fighting ISIS since January.
The Syrian regime of President Bashar Assad, for its part, has escalated its attacks against ISIS positions since the group spearheaded a Sunni militant offensive in neighboring Iraq.
"From 10 June (when Mosul fell from Iraqi government control) to date, the Syrian air force really stepped up its raids against ISIS positions, and there have been strikes every day since then," said Observatory director Rami Abdel-Rahman.
"There has been a marked escalation. The regime fears ISIS getting stronger, especially after it brought in vehicles from Iraq" that the jihadists seized from fleeing troops, he added.