Turkish troops used tear gas to disperse a crowd of Kurds seeking to enter Syria to defend their ethnic kin there against Islamic State, whose advance in the past week has driven tens of thousands to flee.

Kurds clashed with Turkish security forces near the border for a second day Monday, after the main Kurdish parties in Turkey called on people to go to the aid of the Syrian Kurds. Militants have seized dozens of villages around the town of Ayn al-Arab, also known as Kobani to the Kurds, in northern Syria near the Turkish border, forcing the mostly Kurdish residents to flee their homes.

More than 130,000 of them have taken refuge in Turkey, Deputy Prime Minister Bulent Arinc said late Monday after a Cabinet meeting, according to the official Anadolu news agency. Thousands of male refugees found a way back across the border into Syria to rejoin the fight against the militants, after taking their families to safety in Turkey, the Kurdish news agency Firat said.

The Kurds in Syria are the latest group targeted by Islamic State, which has rampaged through the country and neighboring Iraq, declaring a caliphate in the territories it has conquered. The U.S. has vowed to defeat the militants and has been carrying out airstrikes against them in Iraq for about six weeks.

Turkey stayed outside the initial U.S.-led efforts to rally regional support for its campaign against Islamic State, amid concerns about 49 hostages seized by the militants at the Turkish Consulate in Mosul, northern Iraq.

Those captives were released early on Sept. 20, after what Turkish President Recep Tayyip Erdogan described as “political and diplomatic bargaining,” and some described their ordeal in local television interviews.

Even before the flow of Kurdish refugees in the past week, Turkey was hosting about 1.4 million Syrians who fled the country’s three-year civil war, according to officials. The government says it has spent about $3.5 billion to house them.

Turkish authorities and the UNHCR are preparing for the possibility that hundreds of thousands more refugees will cross the border in the coming days, the U.N. refugee agency said on its website. Because Kobani had been largely unscathed during earlier phases of the Syrian war, as many as 200,000 Syrians from other parts of the country had taken refuge there, the UNHCR said.

Islamic State militants now control more than one-third of Turkey’s 900-km border with Syria, Turkish Deputy Premier Numan Kurtulmus said Tuesday. The U.S. is pressing Turkey to impose tighter curbs on border crossings into Syria to stop foreign fighters joining Islamic State.

Asked about reports in local media that Turkey was planning to set up a buffer zone inside Syria, Arinc said the government would only consider such measures in the framework of a United Nations decision.

Kurdish leaders in northern Iraq as well as Turkey have called for international support for the beleaguered Syrian Kurds. The Kurdish government of northern Iraq will consider sending some of its Peshmerga fighters to help the Syrian Kurds, although there are “geographic obstacles,” Premier Nechirvan Barzani said, according to Anadolu.

The Pershmerga are already fighting Islamic State in northern Iraq. The Iraqi Kurds are receiving weapons from the U.S. and European allies to bolster their forces, and they have advanced in coordination with U.S. airstrikes to recapture some territory from the militants.