About 40,000 people, mainly women and children, have been displaced by fighting northwest of Hama city in Syria, the United Nations said on Tuesday.
Since a rebel offensive began in the area a week ago, people have fled south and west to Hama city and to other towns nearby and in neighbouring districts including Homs, Latakia and Tartous, the UN said.
The report said increased clashes between rebels and the Syrian regime army in northern and western Hama have put civilians at risk of injury, death and displacement.
Meanwhile, regime air strikes in rebel-held areas have killed four civilians in the southern Syrian city of Daraa. The city is disputed with rebels holding on to the southern parts, while the regime controls areas in the north.
Clashes raged around a key northern Syrian town on Tuesday after Daesh launched a counter-attack to fend off a US-backed advance near the group's stronghold Raqqa.
Backed by air power from an international coalition, the Syrian Democratic Forces are laying the groundwork for an assault on the heart of Daesh's so-called 'caliphate.'
A key part of the campaign is the battle for the Daesh-held town of Tabqa on the Euphrates River, as well as the adjacent dam and military airport.
The SDF seized the Tabqa airbase late on Sunday and began pushing north towards the town itself, but Daesh fighters doubled down on their defences on Tuesday, the Syrian Observatory for Human Rights said.