A man walks amid smoke and fire following a reported air strike by Syrian government forces in the ISIS group controlled Syrian city of Raqa, on Nov. 25. 2014.

More than 63 people were killed in militant-held Syrian city of Raqqa after Syria regime war planes struck the militant group’s stronghold on Tuesday, an observer group monitoring the war said.

Half of those killed were civilians, Reuters news agency reported adding that Syrian government officials were not immediately available to comment.

Rami Abdulrahman, who runs the Britain-based Observatory, said 10 war planes struck at least 10 times in Raqqa, a stronghold of the ultra-hardline group Islamic State of Iraq and Syria (ISIS).

“The majority of the strikes were in the eastern part of the city,” Abdulrahman said. “At least 36 of those killed are civilians. As for the rest, we are not sure yet if they were fighters.”

According to the Associated Press, the Local Coordination Committees said the strikes killed at least 70 people.

Additionally, another Raqqa-based collective called Raqqa is Being Silently Slaughtered said it documented over 80 deaths.

ISIS, which has seized wide expanses of territory in Iraq and Syria, drove the last Syrian government forces out of Raqqa province in late August. Its fighters seized an air base then, capturing and later executing scores of Syrian soldiers.

An ISIS fighter in the province confirmed that the government carried out the air strikes, which he said killed at least 70 people, Reuters reported.

The Syrian air force has increased its strikes across Syria since a U.S.-led coalition started attacking Islamic State positions inside Syria in September.

Analysts say the increase could be because the Syrian military wants to weaken rebel groups before they get training and equipment promised by the United States.

 
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