The Syrian army has retaken Deir al-Zour, the last major stronghold of so-called Islamic State (IS) in Syria, state TV says.
Other reports said the Syrian army and its allies were clearing the last pockets of resistance from IS.
IS had held most of the city since 2014. It was important because of its proximity to the border with Iraq.
Meanwhile Iraqi forces have entered one of the last towns under IS control on the other side of the border.
Some 350,000 civilians in Syria's Deir al-Zour province have been forced to flee their homes during weeks of fighting.
Significant setback for IS
Jonathan Marcus, BBC diplomatic correspondent
The success of the Syrian government forces inevitably raises the potential for clashes between them and US-backed, predominantly Kurdish units who hold a significant swathe of northern Syria.
It is a powerful reminder that while the war against the IS "caliphate" is well on the way to being won, the situation on the ground in Syria is becoming ever more complex.
With Iran eager to consolidate its influence, questions remain as to the Trump administration's future policy direction now IS is collapsing. Syrian President Bashar al-Assad has consolidated his position and looks to squeeze opposition forces in the months ahead.
Why is Deir al-Zour important?
The city lies on the Euphrates river about halfway between the city of Raqqa, previously the headquarters of IS's self-styled "caliphate", and the Iraqi border.
IS had designated the area on both sides of the border as its "Euphrates Province" and used it to transfer fighters, weapons and goods between Iraq and Syria.
The cross-border province was also a symbol of the jihadists' intention to eradicate all the region's frontiers and lay to rest the 1916 Sykes-Picot agreement, an emblem of the colonial division of the area resented by many Arabs.
Last month a US-backed alliance of Syrian fighters pushed IS out of Raqqa,
In September, the Syrian army broke a siege by IS in part of Deir al-Zour that had trapped an estimated 93,000 civilians in an enclave on western bank of the Euphrates since 2015.
What territory does IS still control?
The militant group is now confined to just a few pockets in Deir al-Zour province.
The Syrian Democratic Forces (SDF) and Syrian government forces - which are backed by Russian air strikes and fighters from Lebanon's Hezbollah movement - have been carrying out separate offensives in Deir al-Zour province with the aim of taking control of Albu Kamal, a key crossing on the border with Iraq.
Slide the button to see how the area IS controls has changed since 2015
In some areas the US-backed SDF and Russia-backed Syrian army have taken up positions just a few kilometres apart.
An SDF spokesman told the BBC they were still encountering some resistance with the militants using suicide cars and trucks, thermal missiles and mortars. In some towns and villages there was house-to-house fighting, Kino Gabriel said.
IS has also suffered a series of defeats in recent months to Iraqi government forces, who are advancing along the Euphrates river on the other side of the border.
Iraqi government forces have entered the IS-held town of al-Qaim, which lies across the border from the Syrian town of Albu Kamal. Soldiers, police, Sunni tribesmen and mostly Shia paramilitary fighters, some backed by Iran, are taking part in the assault.
IS has now been driven out of about 95% of the land the group once held in Iraq and more than 4.4 million Iraqis have been freed from its rule, the US-led coalition fighting IS says.