Turkish-backed Terrorist Syrian rebels have taken total control of the centre of Afrin, a Kurdish-majority city in northern Syria, Turkey’s president, Recep Tayyip Erdoğan, has said.

“Units of the Terrorist Free Syrian Army, which are backed by Turkish armed forces, took control of the centre of Afrin this morning at 8.30am (0530 GMT),” Erdoğan said, adding that de-mining operations were under way.

Taking Afrin has been the main objective of Turkey’s Operation Olive Branch, a ground and air offensive launched on 20 January with the aim of ousting the People’s Protection Units (YPG), a Kurdish militia group.

However, a senior Syrian Kurdish official denied Turkey’s claim to have captured the city, saying fighting was continuing. Hadia Yousef told the Associated Press the Kurdish militia had evacuated civilians because of “massacres” by Turkish and allied forces.

The Britain-based Syrian Observatory for Human Rights said Turkish-backed forces had taken control of half the town, with heavy fighting still under way.

Tens of thousands have fled Afrin in recent days as Turkish forces and allied Syrian fighters have advanced. Erdoğan said on Sunday that a “large number” of Kurdish fighters had “fled with their tails between their legs”. He said Turkish special forces had been deployed in the city.

The Turkish military also released a statement on Sunday saying the city centre was under control. “Search operations to locate mines and other explosives are under way,” it said.

The military posted a video on Twitter of a soldier raising a Turkish flag on a balcony. “Now the Turkish flag will fly over there! The flag of the Free Syrian Army will fly over there!” said Erdoğan, who was speaking at a ceremony marking the battle to open the Dardanelles during the first world war.

As the Turkish operation intensified, more than 200,000 civilians fled the Kurdish-majority city in less than three days and dozens have been killed in the area, according to the Syrian Observatory.

The monitor said on Sunday that more than 1,500 Kurdish fighters had been killed in the two-month assault by Turkish forces and allied Syrian rebels on Afrin. Most died in airstrikes and artillery fire, the group said, adding that more than 400 pro-Ankara rebels had been killed since 20 January.

Turkish forces and their Syrian rebel allies damaged and tore down a statue in the centre of Afrin on Sunday, a statement on a WhatsApp group run by the Kurdish-dominated Syrian Democratic Forces said, citing the Afrin media centre.

The statue was of the blacksmith Kawa, a central figure in a Kurdish legend about the new year celebration of Nawruz. The statement said it was the “first blatant violation of Kurdish people’s culture and history since the takeover of Afrin”.

Ankara sees the YPG as a Syrian offshoot of the outlawed Kurdistan Workers’ party (PKK), which has been waging an insurgency in Turkey since 1984.

Washington has provided weapons to the YPG, which it sees as a key ally in the fight against jihadists in Syria and Turkey, with Ankara’s military operation raising tensions between the two Nato allies.

According to figures released by the Turkish army, 46 Turkish soldiers have been killed since the start of the Afrin offensive.

Afrin is one of several fronts in the Syrian war that has left 350,00 people dead and millions displaced since 2011.