The Islamic State militant group have executed Syrian soldiers and taken hostages after taking control of an air base in the Raqqa region of Syria over the weekend.

The executions and hostages were shown in photographs on Facebook pages of Islamic State supporters, according to a report from Reuters. The Syrian media has offered its citizens little coverage of the events on the Tabqa air base, angering many in the country.

Those photos show ISIS militants -- who are masked -- killing no fewer than seven men who were identified as Syrian soldiers, as well as more than 20 soldiers who appeared to have been taken hostage on the air base.

ISIS rushed the Tabqa air base on Sunday after battles with Syrian forces that left more than 500 people dead, according to the Syrian Observatory for Human Rights.

The air base was one of the last areas held by Syrian forces in the Raqqa province, and the loss of the base signifies near total control of that region for ISIS. Raqqa is adjacent to the Allepo province, which ISIS are reportedly targeting. Allepo would offer many strategic advantages for the militants.

Over the past two months, ISIS has staged a heavy offensive in neighboring Iraq, taking large swaths of territory, but recently has been beaten back in that country by U.S. air strikes. The siege on the air base was an indication of a renewed focus in Syria.

U.S. President Barack Obama on Tuesday authorized drones to start surveillance flights over Syria, which could suggest the U.S. is planning air strikes soon, according to CNN. The White House would not confirm.

The Syrian government, led by Bashar al-Assad, has asked for international assistance in dealing with ISIS. The U.S. does not recognize al-Assad as the leader of Syria and has said that if it does launch air strikes, it will not be in conjunction with any efforts by the Syrian regime.