For days, residents of the east Syrian city of Dair Alzour had heard the thumping soundtrack of war getting nearer.
It was a cause for celebration.
Since 2015, the city, home to an estimated 93,500 people, had suffered under a crippling siege by Islamic State. The militants had overrun most of the surrounding province a year earlier, but had been kept at bay by some 5,000 to 10,000 exhausted Syrian troops barely sustained by airdrops of supplies.
But on Tuesday, the Syrian military and its battlefield allies punched through Islamic State positions and linked up with soldiers bunkered in a base on the outskirts of Dair Alzour, state media and activists said, ending the almost three-year blockade.
The army's general command said that the breakthrough came as a result of "unique and heroic operations" and that it represented a "significant launching pad to expanding military operations in the area and its environs to destroy what remains of the terrorist Daesh organization," referring to Islamic State by its Arabic acronym.
"This achievement … confirms the ability of the Syrian army and its allies … to bring about a complete defeat of the terrorist project in Syria."
The state news agency, SANA, also reported that Syrian President Bashar Assad congratulated the commanders of the defending troops via telephone on "their steadfastness in the face of the harshest of terrorist organizations on earth" and thanked them for "their sacrifices."
"You are today beside your colleagues … to clean the entire area from the evil of terrorism and restore peace and security to every last inch of the lands."
The breaking of the siege provided a measure of relief for those who lived in Dair Alzour. The city had been the frequent target of shells, car bombs and suicide bombers dispatched by the militants. In January, a blitz Islamic State offensive divided the city in two, but also threatened the vital airdrops conducted by the World Food Program, the only real source of aid.
Forces loyal to Assad, backed by Russian air power, had begun a wide-scale offensive aimed at eastern Syria weeks earlier. They clawed back wide swaths of open desert — and precious oil fields — that had fallen into the militants' hands before reaching the edge of Brigade 137, the base on the city's outskirts, on Monday. Defending troops in the city, meanwhile, had cleared pathways of minefields before the government advance, and residents began to celebrate.
The Syrian Observatory for Human Rights, a pro-opposition watchdog, said that incoming troops had entered Brigade 137 as well as 10 government-controlled neighborhoods. However, the head of the monitoring group, Rami Abdul Rahman, said there was still more to do.
"The important matter is that they broke the siege, yes, but half the city is still with Daesh, and that will require a battle," he said in a phone interview Tuesday. He added that government troops were advancing on Islamic State-held neighborhoods.
The victory comes at a pivotal time for the government. Having cemented its grip on what has come to be called "useful Syria" (Damascus, Homs, the coastal Mediterranean region and Aleppo), it has turned its sights to Dair Alzour province, which is rich in oil, mineral and water resources.
Yet it faces competition from several U.S.-backed factions seeking to fill the vacuum left by Islamic State, including the Kurdish-dominated Syrian Democratic Forces (now fighting Islamic State in Raqqah) as well as CIA- and Pentagon-supported rebel groups operating in Syria's southeastern corner. But a win in Dair Alzour would present an accomplishment its adversaries would not be able to counter.
Islamic State, meanwhile, is being squeezed on all fronts of its once-sprawling, self-declared caliphate. It has lost Mosul, the Iraqi city, and much of Raqqah, the Syrian city that is the group's de facto capital. A defeat in Dair Alzour, the group's last significant bastion in eastern Syria, would also deny it access to its heartland areas in Iraq.
3:40 p.m.: This article has been updated throughout with staff reporting.