The Russian Defense Ministry reported on the recent casualties among Russian military in Syria amid the operation to free the city of Deir ez-Zor.

Axar.az reports that two Russian contract servicemen have been killed in mortar shelling by ISIS terrorists in the Syrian province of Deir ez-Zor, the Russian Defense Ministry said Monday.

"Contract servicemen accompanied a car convoy of the Russian Center for the Syrian reconciliation. When traveling in the province of Deir ez-Zor, was shelled by mortar rounds fired by ISIS terrorists," the ministry said in a statement.

According to the statement, a Russian serviceman was killed on site, while another one was seriously injured.

"The wounded serviceman was promptly taken to a hospital where Russian military doctors fought for his life, but his injuries proved to be mortal," the statement said.

The Russian Defense Ministry announced earlier in the day that the Syrian government forces had driven ISIS terrorists out of key positions on the Palmyra-Deir ez-Zor highway.

The Syrian army supported by the Russian Aerospace Forces has been advancing toward Deir ez-Zor from three directions as part of the campaign to free the city launched in August.

Deir ez-Zor, located on the shores of the Euphrates River to the northeast of Damascus, and a military airfield near the city have been besieged by ISIS for over three years, with food and ammunition only being delivered by air, while helicopters from the city of Qamishli have been evacuating the wounded and delivering essential supplies to the city's population.

The lifting of the siege of Deir ez-Zor will lead to the complete defeat of the most combat-effective formations of the ISIS terrorist group in Syria, the chief of the Russian General Staff's Main Operational Directorate said earlier.