AFP journalists said the hundreds of young demonstrators fought back by hurling rocks and setting up barricades on the road leading to a nearby border crossing.

"We've come to support our brothers in Syria under attack by Daesh," Turkish Kurdish demonstrator Mehmet Eminakma told AFP, referring to the Islamic State (IS) jihadist group.

He said that Turkish authorities were blocking young Syrian Kurds who had accompanied their families to safety inside Turkey from returning to the battlefront.

The security forces forced demonstrators away from a barbed wire border fence that stands just five kilometres (three miles) from the town of Ain al-Arab, where Kurdish fighters are confronting the jihadists.

After the clashes, security forces closed most of the eight crossing points in the area, including one used by Kurdish fighters heading to Syria. Only two posts remain open, and the interior ministry will now register new arrivals.

As many as 70,000 Syrian Kurds have poured into Turkey since Friday fleeing the IS offensive in northeastern Syria, according to the UN's refugee agency, UNHCR.

IS extremists seized dozens of villages in a lightning offensive as they closed in on Kobane, prompting a mass exodus of residents. Witnesses told AFP that Kurdish fighters were clashing with IS in a village 10 kilometres away from the town.

Turkey, which has given shelter to some 1.5 million refugees from the Syrian conflict, had been refusing to accept any more for fear of being overwhelmed.

President Recep Tayyip Erdogan on Sunday described the refugee influx as a "major problem" while saying Turkey would continue to welcome those fleeing the IS offensive.

"It comes with problems attached, we are very well aware of it, but it would be really cruel to leave their destiny in the hands of fate," Erdogan said.

"How can we sit back and watch when they are being bombed? We are embracing everyone regardless of their ethnicity, religion or sect," he said.

"There are good people and bad people in every nation, but we have to fullfil our duties as humans and Muslims."

Three lawmakers from Turkey's pro-Kurdish People's Democracy Party travelled to Switzerland on Sunday to begin a hunger strike outside the UN office in Geneva to press the international community to take action.

And in Istanbul, around 10,000 people staged a solidarity protest in Istiklal Avenue, the city's main pedestrian area, shouting anti-government and anti-IS slogans.

Protesters repeatedly chanted "Kurdistan will be a grave for IS" and carried banners including one that read: Killer IS, collaborator AKP (the ruling Turkish Justice and Development Party)"

Ankara stands accused of indirectly helping to create the IS through its support of Islamist elements within the Syrian rebellion against President Bashar al-Assad.