Syria's army declared victory over Islamic State on Thursday, saying its capture of the jihadists' last town in the country marked the collapse of their project in the region.
The army and its allies are still fighting Islamic State in desert areas near Albu Kamal, the last town the militant group had held in Syria, near the border with Iraq, the army said.
But the capture of the town ends Islamic State's era of territorial rule over the so-called caliphate that it proclaimed in 2014 across Iraq and Syria and in which millions suffered under its hardline, repressive strictures.
Yet after ferocious defensive battles in its most important cities this year, where its fighters bled for every house and street, its final collapse has come with lightning speed.
Instead of a battle to the death as they mounted a last stand in the Euphrates valley towns and villages near the border between Iraq and Syria, many fighters surrendered or fled.
In Albu Kamal, the jihadists had fought fiercely, said a commander in the pro-Syrian government military alliance. But it was captured the same day the assault began.
This sealed "the fall of the terrorist Daesh organisation's project in the region", an army statement said, using an Arabic term for Islamic State.
The fate of its last commanders is still unknown, killed by bombardment or in battle, taken prisoner but unidentified, or hunkered into long-prepared hideouts to plot a new insurgency.
The last appearance of Abu Bakr al-Baghdadi, who declared himself caliph and heir to Islam's historic leaders from the great medieval mosque in Iraq's Mosul, was made in an audio recording in September.
Western security chiefs have also said its loss of territory does not mean an end to the "lone-wolf" attacks with guns, knives or trucks ploughing into civilians that its supporters have mounted around the world.
Middle East chaos
As it did after previous setbacks, Islamic State's leadership may now stay underground and wait for a new opportunity to take advantage of the chaos in the Middle East.
It might not have long to wait. In Iraq, a referendum on independence in the northern Kurdish region has already prompted a major confrontation between its autonomous government and Baghdad, backed by neighbouring Iran and Turkey.
In Syria, it was two rival campaigns that raced across the country's east this year, driving back Islamic State, the Syrian army backed by Russia, Iran and Shia militias, and an alliance of Kurdish and Arab militias backed by the United States.
Syrian officials and a senior advisor to Iran have indicated the Syrian army will now stake its claim to Kurdish-held territory. Washington has not yet said how it would respond to a protracted military campaign against its allies.
Aggravating the region's tensions, and raising the possibility of turmoil from which Islamic State could benefit, is a contest for power between Iran and Saudi Arabia.
