The Syrian Army has taken control of oilfields and a gas refinery near Deir ez Zor, according to a state news outlet Russia Today.
The city, the largest in eastern Syria, has been caught up in the civil war engulfing the country.
It comes as President Bashar Al-Assad’s forces march on the banks of Euphrates River.
The oil rich province has been locked into a race between the incumbent Syrian government forces and the US backed rebel group the Syrian Democratic Forces.
The area was formerly under the control of ISIS.