An alliance of Kurdish and Arab forces, known as the Syrian Democratic Forces or SDF, entered the Islamic State group-held city of Manbij in northern Syria Thursday night, a monitoring group said.
Fighters of the Syrian Democratic Forces managed to enter the city with support from airstrikes by a U.S.-led coalition, the U.K.-based opposition Syrian Observatory for Human Rights said.
"The SDF entered Manbij from the south under cover of coalition air raids," said the Observatory's chief Rami Abdel Rahman, whose Britain-based group relies on a broad network of sources inside Syria to monitor the country's conflict.
He said there was "fierce street fighting between buildings" and that at least two SDF fighters had died when a bomb went off in a residential building.
The SDF has faced fierce resistance from the Islamic state group since launching the assault to take Manbij on May 31. It managed to encircle the city earlier this month but its advance slowed as the extremist group fought back with almost daily suicide bombings.
The Islamic State group have held the city since 2014, the year it seized control of large parts of Syria and neighboring Iraq and declared its "caliphate."
Manbij, which had a population of about 120,000 before the start of Syria's civil war in 2011, is a key point on the extremist group’s supply route from the Turkish border to its de facto Syrian capital of Raqqa.
The U.S.-led coalition also confirmed that the SDF is moving closer toward taking over the city.
"So there is still a civilian population, there are Daesh in defensive areas and the Syrian Democratic Forces are moving closer to them," said British Army Major General Doug Chalmers, deputy commander for strategy and sustainment with the U.S.-led coalition, using an Arabic acronym for the Islamic State group.
The SDF has so far taken 28 villages from the Islamic State group in its push toward Manbij, according to the Syrian Observatory.
The multi-ethnic group had also freed more than a dozen women from the Yazidi minority who were taken by Islamic State group fighters from Sinjar in Iraq.
Other enemies of the Islamic State group, including the governments of Syria and Iraq, also launched major offensives on other fronts, in what amounts to the most sustained pressure on the militants since they proclaimed their caliphate in 2014.