Kurdish militia drove the Islamic State group from the Syrian town of Kobane and raised their flags on Monday, dealing the jihadists an important blow after months of heavy fighting.
Across the border in Iraq, meanwhile, a top army officer announced troops had "liberated" Diyala province from IS jihadists.
In Syria, the Kurdish advance in Kobane, on the frontier with Turkey, marked the culmination of a battle lasting more than four months in which nearly 1,800 people were killed.
The Syrian Observatory for Human Rights said the Kurdish People's Protection Units (YPG) had "expelled all Islamic State fighters from Kobane and have full control of the town".
"The Kurds are pursuing some jihadists on the eastern outskirts of Kobane, but there is no more fighting inside now," said the Observatory's Rami Abdel Rahman.
US Central Command said Kurdish forces now had control of 90 percent of Kobane.
"While the fight against ISIL (IS) is far from over, ISIL's failure in Kobane has denied them one of their strategic objectives," Central Command said in a statement.
Kurdish forces were carrying out "mopping-up operations" against remaining IS forces in the Maqtala district, on the town's eastern outskirts.
YPG spokesman Polat Jan also announced the news on Twitter, writing: "Congratulations to humanity, Kurdistan, and the people of Kobane on the liberation of Kobane."
Mustafa Ebdi, an activist from the town, said the "fighting has stopped".
YPG forces were "advancing carefully in Maqtala because of the threat of mines and car bombs," he added.
The United States, which has led a coalition bombing IS forces in Syria and Iraq, was cautious, declining to confirm an end to the battle.
The Kurdish advance came after the Pentagon said the international coalition had carried out 17 air strikes against jihadist positions in Kobane within 24 hours.
The targets included "tactical units" and "fighting positions" as well as an IS vehicle and staging areas.
The loss of Kobane, also known as Ain al-Arab, would be an important defeat for IS.
The group has lost 1,196 fighters since it began its advance on the town on September 16, said the British-based Observatory.
At one point, the jihadist group had looked poised to overrun Kobane.
IS wielded sophisticated weapons captured from military bases in Syria and Iraq and committed hundreds of fighters to the battle.
But Kurdish forces gradually pushed back the jihadists with the help of the US-led air raids and a group of fighters from Iraq's Kurdish peshmerga forces.
Analysts say the loss of Kobane is both a symbolic and strategic blow for IS, which set its sights on the small town in a bid to cement its control over a long stretch of the Syrian-Turkish border.
Since the group emerged in its current form in 2013, it has captured large swaths of territory in both Syria and Iraq.
It has declared an Islamic "caliphate" in territory under its control, and gained a reputation for brutality, including executions and torture.
But its apparent failure in Kobane could put the brakes on its plans for expansion in Syria.
"Despite all that manpower, all that sophisticated weaponry, IS couldn't get the city, so it's a big blow for their plans and its a great achievement for the Kurds," said analyst Mutlu Civiroglu.
"Kobane sets an example on the ground, showing that when you have skilled fighters on the ground with the support of air strikes, this danger, these forces, can be stopped and eliminated."
Civilians were largely spared in the fighting because they evacuated en masse, mostly across the border into Turkey, in the early stages of the battle.
Over the border in Iraq, the army announced another defeat for IS, with the recapture of Diyala province.
"We announce the liberation of Diyala from the (IS) organisation," Staff Lieutenant General Abdulamir al-Zaidi said.
"Iraqi forces are in complete control of all the cities and districts and subdistricts of Diyala province."
The general said there would still be clashes however against IS in the rural Hamreen mountains, which stretch across multiple provinces, including Diyala.
Among international forces training the Iraqi military, Canadian special forces have twice exchanged gunfire with IS fighters since the first confirmed ground battle in Iraq between Western troops and the jihadists earlier this month, a senior officer in Ottawa said.
"Two similar events have occurred over the last week and, in both cases, Canadian special operations forces, again acting in self-defence, effectively returned fire, neutralising the threat," said Captain Paul Forget.
No Canadians were injured.