Syria has launched airstrikes against Islamic State group forces in Palmyra. According to the Syrian Observatory for Human Rights, the Syrian government launched 15 strikes in the ancient city.

The airstrikes came after the government forces withdrew from Palmyra. According to the monitoring group, the airstrikes killed at least four civilians. These were the most intense raids since the Islamic State group -- also known as ISIS or ISIL -- took control of the Syrian city last week.

Turkey said that it had reached an agreement with the United States to provide air support to Syria. Foreign Minister Mevlut Cavusoglu said that the air support would protect some of the mainstream rebels trained through a U.S.-led program.  

Cavusoglu said that the rebel forces must be supported through air. He said that there was a “principle agreement” regarding the air support. The Turkish foreign minister said that it was the army’s responsibility to decide how it would provide the support.

The ongoing raids are confirmed by a military source as well. "Military operations, including air raids, are ongoing in the area around Al-Suknah, Palmyra, the Arak and Al-Hail gas fields and all the roads leading to Palmyra," ABC News quoted him as saying. "We are pursuing [IS] wherever they are."

The government strikes targeted specific areas in the city. Director Rami Abdel Rahman said that some of the raids had taken place close to a Unesco world heritage site. He said that several people had been injured in the strikes.

According to Rahman, ISIS suffered losses after a military security building had been hit. He said that some of the airstrikes were close to the Greco-Roman ruins which the city had been famous for. Reuters reported that the airstrikes had targeted the city hospital.

The monitor group said that around 600 people had been taken hostage by the extremist group. Around 217 people have been killed by the group so far. There are 67 civilians among the dead including 14 children. Some of the executions by ISIS were performed by beheading.

According the Syrian state media, there have been at least 400 civilian casualties in Palmyra. Most of the executed people are children, women and old men.