Syrian government troops were engaged in a counterattack against Islamist rebels and their allies on Wednesday as the two sides grappled for control of the key city of Hama.

According to the UK-based Syrian Observatory for Human Rights (SOHR), the forces of President Bashar al-Assad have suffered several major defeats since Hayat Tahrir al-Sham (HTS) rebels and their allies launched a surprise offensive last week.

After sweeping through Aleppo, the rebels — whose roots come from the Syrian branch of al-Qaeda — are now trying to capture Hama, a strategically important city that connects Aleppo and the capital Damascus.

The capture of Aleppo was significant. In over a decade of civil war, it never fell out of government control to either the moderate rebels or the "Islamic State" (IS) extremists.

By late on Tuesday, rebels had advanced up to the city gates of Hama. The city was a center of the 2011 protest movement, triggering Assad's brutal clampdown that launched the Syrian Civil War.

Assad less in control than thought

The province around Hama is home to the Alawite community from which Assad hails, and the rebels' actions may cut the president off from the base of support he relies on to shore up his power.

Experts and monitors have said that recent events show that Assad was never as totally in control of the country as he has projected in recent years. There have been reports of Russia, a longtime ally of Assad, rejoining the fight with airstrikes.

Hundreds of people, mostly fighters, have been killed in the recent spate of violence, and tens of thousands have had to flee their homes.

es/rc (AP, AFP)