Deir al-Zor is the largest and most important city in eastern Syria, and is the center of the country’s oil production.
“The armed forces, in cooperation with allied forces, liberated the city of Deir al-Zor completely from the clutches of the Daesh terrorist organization,” the military source said, using an Arabic acronym for Islamic State.
The army, backed by Russian bombers, Iran and Shi‘ite militias, is advancing toward the last significant town held by Islamic State in Syria, Albu Kamal, which is also located on the western bank of the Euphrates.
A rival offensive by Kurdish and Arab militias supported by a U.S.-led coalition with air strikes and special forces, is pressing Islamic State on the eastern bank.
Iraqi forces on Friday said they had begun their own final offensive against Islamic State on the Iraqi side of the jihadist territory that straddles the border between the two countries, entering the city of al-Qaim.
As it was reported earlier militants of the Islamic State killed 128 people in October, as they suspected the people of collaborating with the Syrian regime, according to Al Arabiya.
"ISIS has over a period of 20 days executed more than 116 civilians in reprisal killings, accusing them of collaboration with regime forces," said Rami Abdel Rahman, head of the Britain-based Syrian Observatory for Human Rights monitor.
Later the number was specified to 128.