At least 15 civilians, including three teenagers, have been killed in air raids in the Syrian town of Douma.
The civilians died during eight raids by Syrian militants in several districts of the town, 13km northeast of Damascus, according to the Syrian Observatory for Human Rights.
Meanwhile, the US military has said it is unaware of any flight operations by the Islamic State group "in Syria or elsewhere".
This comes in response to reports that IS militants were being trained to fly in three captured fighter jets.
"We are not aware of ISIL conducting any flight operations in Syria or elsewhere," a spokesperson for the Central Command spokesman said today.
Rami Abdul Rahman, of the observatory, said the IS group has been flying the planes over the captured al-Jarrah military airport east of the Syrian city of Aleppo.
"We continue to keep a close eye on ISIL activity in Syria and Iraq and will continue to conduct strikes against their equipment, facilities, fighters and centres of gravity, wherever they may be," the Central Command spokesperson said.
General Lloyd Austin, commander of the US-led air war against IS, has said that there have been "encouraging" signs in recent days in the Syrian border town of Kobane.
While General Austin said that signs were promising, he acknowledged that it was "highly possible" the town on the Syrian-Turkish border could fall to the extremists.
Meanwhile, Iraqi security forces are battling IS militants in the strategic city of Ramadi, to the west of Baghdad, and near militant-held Tikrit to the north.
Ramadi is one of a falling number of areas that pro-government forces still control and its loss would be a major blow.
Deputy provincial council chief Faleh al-Essawi said security forces attacked IS fighters in three different areas of Ramadi and repelled an assault by the militants from the city's north.
A police major said an IS attack from the western side of Ramadi was also held off by security forces and allied tribesmen.
Mr Essawi reiterated that foreign support will be needed to retake the city, saying Iraqi forces cannot do it on their own.
