The Syrian army and its allies were fighting on Saturday in Islamic State's last pocket in central Syria after taking the heavily defended village of Uqairabat on Friday, a war monitor reported.

The enclave lies close to the main road running between the cities of Homs and Aleppo near the town of al-Salamiya, and has been the site of intense fighting for months. Evicting jihadists from the area is viewed as necessary to improve security on the road.

The Syrian army, aided by Russian airstrikes and Iran-backed Shi'ite militias including Lebanon's Hezbollah, has advanced deep into eastern Syria this year against Islamic State.

It is pushing to relieve its besieged enclave in the city of Deir al-Zor, one of the cities on the Euphrates to which Islamic State has fallen back after losses in both Syria and Iraq, but has left the pocket in central Syria in its rear.

Late on Friday, a military media unit run by Hezbollah said the army had captured Uqairabat, which it described as Islamic State's stronghold in that region.

The war monitor, the Britain-based Syrian Observatory for Human Rights, said the army and its allies had also taken other villages in the area, aided by Russian helicopters, and reported that intense fighting continued.