The regime army and its allies recaptured an oilfield from Daesh near the eastern city of Deir el-Zour on Saturday in further advances against the militants, Assad regime TV reported.

Regime forces also seized part of a main highway running from Deir el-Zour down to the city of al-Mayadeen, to which many Daesh terrorists have retreated, the Syrian Observatory for Human Rights monitoring group said.

The regime army this week broke through Daesh lines to reach a government-held enclave of Deir el-Zour besieged for years by the terrorists, and is fighting to reach a nearby air base which Daesh still surrounds.

On Saturday, the army and militias fighting alongside it seized the Teym oilfield in desert south of Deir el-Zour, state TV said. Deir el-Zour is in an oil-rich area of Syria.

To the east of Teym and south of the air base, regime forces also recaptured part of the main road running from Deir el-Zour to al-Mayadeen, downstream along the Euphrates river and closer to the Iraq border, the Observatory reported.

The British-based monitoring group said that advance would block potential Daesh reinforcements from al-Mayadeen.

The advances put yet more pressure on Daesh's shrinking territories, which once stretched across northern and eastern Syria, and northwestern Iraq.

In Syria, the group holds much of Deir el-Zour province and half the city, as well as a pocket of territory near Hama and Homs in the west of the country.