Rebels say they are confident of success in the northwestern Syrian city. The push comes a day after Turkish President Recep Tayyip Erdogan vowed to get rid of Daesh.
Turkish troops and Syrian rebel fighters are pushing deeper into the Daesh stronghold al-Bab in Syria after entering the town from three sides, rebels said.
The latest push comes a day after President Recep Tayyip Erdogan vowed to capture al-Bab soon. War monitoring groups and activists in Syria said the fight for al-Bab has transitioned into an urban war after opposition forces managed to advance and capture several buildings and roundabouts in the northern and western sides of the city.
TRT World's Iolo Ap Dafydd has more details.
Both Turkey's foreign minister and president have suggested Turkey will continue its fight in Syria under Operation Euphrates Shield – a military action that started in August 2016 to secure Turkey's border with Syria – once the town of al-Bab is retaken from Daesh.
The Turkish president, who is on a four-day visit to the Gulf states, indicated on Sunday that the Turkish forces could also be involved in the fight to remove Daesh from the group's de facto Syrian capital of Raqqa.
"Al-Bab will be soon cleared from Daesh. Then to the east there are issues of Manbij and Raqqa that need to be resolved. We shared our views with the new US administration and CIA, and we will follow the developments in line with our stance," Erdogan said.
"The ultimate goal is to clear a 4,000 to 5,000 square kilometre area and create a terror-free safe zone in northern Syria. This safe zone will counter the refugee crisis and give them a place to settle," he said.
Syrian regime leader Bashar al-Assad on Friday slammed the idea of US-established safe zones, saying a secure country was a more viable option.
Turkey-backed Free Syria Army (FSA) fighters said they are confident of the al-Bab victory.
"For three days, the operation has been continuous and we continue fighting. We have captured the public hospital and Sheikh Aqeel mountain, and there are now clashes inside the town. Hopefully, we will declare al-Bab liberated within the coming few days," said Muhammad Altaweel, the commander of FSA's al-Bab military council.
The battle for al-Bab has been longer than expected, gruelling and more brutal than hoped for, but an even bigger battle at Daesh's headquarters in Raqqa is on the horizon.
The Syrian conflict began in March 2011 with anti-government protests. Successive rounds of peace talks have failed to produce a political solution. The war has killed hundreds of thousands of people, made more than half the country's population homeless, and created the world's worst refugee crisis since World War II.