The Syrian army and its allies recaptured an oilfield from Islamic State near the eastern city of Deir al-Zor on Saturday in further advances against the militants, state TV reported.
Government forces also seized part of a main highway running from Deir al-Zor down to the city of al-Mayadeen, to which many Islamic State militants have retreated, the Syrian Observatory for Human Rights monitoring group said.
The Syrian army this week broke through Islamic State lines to reach a government-held enclave of Deir al-Zor besieged for years by the jihadists, and is fighting to reach a nearby air base which IS still surrounds.
On Saturday, the army and militias fighting alongside it seized the Teym oilfield in desert south of Deir al-Zor, state TV said. Deir al-Zor is in an oil-rich area of Syria.
To the east of Teym and south of the air base, government forces also recaptured part of the main road running from Deir al-Zor 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 Islamic State reinforcements from al-Mayadeen.
The advances put yet more pressure on Islamic State's shrinking caliphate, which once stretched across northern and eastern Syria, and northwestern Iraq.
In Syria, the group holds much of Deir al-Zor province and half the city, as well as a pocket of territory near Hama and Homs in the west of the country.
