UPDATE 2-Syrian rebel fighters enter Afrin town, say Kurdish forces have pulled out

pulled out@ (Adds Erdogan comments, Turkish army)

ISTANBUL, March 18 (Reuters) - Turkish forces and their Syrian rebel allies swept into the northwestern Syrian town of Afrin on Sunday, taking control of the town center after Kurdish YPG forces pulled out, Turkish President Tayyip Erdogan said.

A spokesman for the rebel fighters said they entered Afrin before dawn from three fronts, meeting no resistance.

But a war monitor said clashes continued in parts of Afrin, the main town of the Afrin region which has been under Kurdish control for years. Afrin is one of three Kurdish cantons in northern Syria on the border with Turkey.

The fighting in a once stable pocket of northwest Syria has opened a new front in the country's multi-sided civil war, highlighting the ever greater role of foreign powers in the seven-year-old conflict.

Ankara, which says Syrian Kurdish YPG fighters are an extension of a militant group waging an insurgency inside Turkey, launched its campaign eight weeks ago and says it will extend the offensive to other Kurdish regions where U.S. forces are stationed alongside the YPG, an ally against Islamic State.

"Afrin city center is under control as of 8:30 this morning," Erdogan told a rally marking the 103rd anniversary of the World War One Gallipoli campaign. Turkish and Free Syrian Army flags had been raised in Afrin, he said.

"Most of the terrorists have already fled with tails between their legs. Our special forces and members of the Free Syrian Army are cleaning the remains and the traps they left behind," Erdogan said. "In the center of Afrin, symbols of trust and stability are waving instead of rags of terrorists."

There was no immediate comment from the Kurdish forces.

Turkey's armed forces said in a statement that troops were combing the streets for mines and improvised explosive devices. The army posted video it said was filmed in the center of Afrin, showing a tank stationed under a balcony draped in the Turkish flag, with an FSA banner being waved.

Free Syrian Army spokesman Mohammad al-Hamadeen said the fighters entered the town from the north, east and west. "Maybe it will be cleared by the end of the day -- it's empty of (YPG) fighters, they cleared out."

The Syrian Observatory for Human Rights, a monitor based in Britain, said Turkish and FSA fighters controlled around half of the town, but fighting continued on Sunday morning in some areas.

Despite an exodus of more than 150,000 people in recent days, thousands of civilians remained in Afrin, it said. (Additional reporting by Yesim Dikmen and Irem Koca in Istanbul and Lisa Barrington in Beirut Editing by Catherine Evans)