DAMASCUS, June 22 (Xinhua) -- A total of seven civilians and 14 Islamic State (IS) militants were killed by U.S.-led airstrikes on an IS-held town in Syria's eastern province of Deir al-Zour, a monitor group reported Friday.

The airstrikes, which have been going on over the past 24 hours, targeted the town of Shufeh, one of the few remaining IS-held areas in the countryside of Deir al-Zour, according to the London-based Syrian Observatory for Human Rights.

The death toll could rise as many of the wounded are in critical condition, the watchdog group said.

Meanwhile, the U.S.-led coalition dropped leaflets over the village of Hajin and Abu Khater area in the countryside of Deir al-Zour to undermine the morale of IS militants after failing to storm those areas on the ground, the pro-rebel group added.

State news agency SANA also reported the U.S.-led airstrikes on Deir al-Zour, saying eight people were killed.

The attack led to major destruction in the houses and infrastructure in the Shufeh, SANA added.

The Syrian government has repeatedly accused the U.S.-led coalition of targeting civilians in Syria, saying the U.S. operations in Syria are illegitimate.

SANA said more than 60 civilians have been killed since the beginning of June in Deir al-Zour by the U.S.-led airstrikes.

The Syrian army has captured large swathes of areas in Deir al-Zour and its countryside with the help of Iran-backed fighters, while the U.S.-backed Syrian Democratic Forces are trying to defeat the IS in its last stronghold on the eastern bank of Euphrates River.