- Video report by ITV News International Affairs Editor Rageh Omaar
Syrian Government troops announced they have liberated the eastern city of Deir al-Zour from the so-called Islamic State group.
The army says it is now in full control of the long-contested city as it flushes out the terror group from its last remaining strongholds in the oil-rich province bordering Iraq.
A statement said that all IS fighters appear to have fled or been killed, but they are still working to remove booby traps and mines left as the militants retreated.
Deir el-Zour, on the west bank of the Euphrates River, had been divided into a government-held and an IS-held part for nearly three years.
Syrian Government forces - backed by Russian troops - first launched an offensive to retake the entirety of the city in September.
They have been steadily making advances and beating back the militant group over recent weeks.
"Army units, in co-operation with allied forces, liberated the city of Deir al-Zour completely from the Daesh terrorist organisation," the military statement said, using the Arabic name for IS.
Footage posted on the website of the Syrian state news agency Sana shows the last moments of the fighting between the Syrian army and IS in Deir el-Zour.
Plumes of smoke are seen rising over the city's IS-held and mostly destroyed neighborhoods of Jamiayat and Jabiliyeh before they were liberated.
The victory marks a significant symbolic defeat for IS, which has seen a series of its former strongholds recaptured as its so-called caliphate crumbles.
Deir al-Zour is the largest city in eastern Syria and represents a significant loss for the terror group. IS' other urban territories including Mosul in Iraq and Raqqa in northern Syria have also almost all been liberated.
The Syrian army are now racing to take the rest of the oil-rich eastern province of Deir al-Zour, including the key town of Boukamal near the Iraqi border.
Meanwhile, Iraqi forces and allied Shiite militiamen are chasing IS remnants inside the town of Qaim, on the Iraqi side of the border.