Syrian Kurds battled to defend a key border town from an Islamic State advance on Monday as Kurdish youths from neighboring Turkey rushed to their aid, heightening the pressure on Ankara.Turkish Deputy Prime Minister Numan Kurtulmus said more than 130,000 Syrian Kurds had fled to Turkey since Friday. Security forces fired tear gas and water cannon at hundreds of Kurdish protesters who accuse Ankara of favoring Islamic State against the Kurds.The main Kurdish armed group in northern Syria, the YPG, said its fighters had halted the Islamic State advance east of the predominantly Kurdish town of Kobani, also known as Ayn al-Arab, but that fierce fighting was continuing.Hundreds of Kurdish youths gathered on the Turkish side of the border, responding to calls from Kurdish leaders to join the fight against Islamic State fighters who have seized swathes of Iraq and Syria and proclaimed a caliphate.Residents fleeing Kobani said the militants were executing people of all ages in villages they seized. Kurds are mostly Sunni Muslims but Islamic State views them as apostates because of their secular ideology. It has persecuted and killed Shi'ite Muslims, Christians and members of the ancient Yazidi sect as well as moderate Sunnis who reject its stark version of Islam.Turkish security forces are now trying to keep Kurds from crossing the frontier to aid their brethren. At the Mursitpinar border crossing, a line of paramilitary police stood guard along a barbed-wire border fence."We all want to cross the border. We tried yesterday but they attacked us, and we will try again today," said balaclava-clad Kurdish activist Shirwan, 28, holding a large PKK flag.Ismet, 19, a local man who makes a living collecting strawberries, said the protesters had gathered from cities across Turkey's predominantly Kurdish southeast: "They are not from around here. They come from Sirnak, Van, Mardin, Nusaybin."He said several hundred Turkish Kurds had already crossed to join the fight. Other residents put the figure higher.The advances by the Sunni insurgents just across Turkey's southern border have alarmed Ankara. But so far Turkey has balked at joining a coalition to fight Islamic State, worried in part about links between the Syrian Kurds and Turkey's own Kurdistan Workers' Party (PKK), which waged an armed campaign for Kurdish rights over several decades.In addition, in the regional sectarian confrontation between Sunnis and Shi’ites, Turkey has thrown its support behind revolutionary Sunni movements amid reports about aid to radical Isalmist groups.Turkey’s Today’s Zaman reported on Monday that a suspected Islamic State member is being treated in the country’s Mehmet Akif Inan State Hospital. Ammar Alo was reportedly taken to a private hospital at first before he was moved on Monday morning to the state hospital in critical condition.Turkey strongly denies it has given any form of support to the Islamist militants, but Western countries say its open borders during Syria's three-year civil war allowed Islamic State and other radical groups to grow in power.The PKK called Turkey's Kurds to arms on Sunday, saying "supporting this heroic resistance" in Kobani was a "debt of honor". Radio stations played patriotic Kurdish songs about heroic fighters and martyrs and one played recordings of PKK commander Murat Karayilan in a bid to drum up support.Meanwhile, the US upped pressure on the fellow NATO member to participate in the US led coalition against the Islamic State, now that the terror group released 49 of its hostages in conditions that remain unclear.US Secretary of State John Kerry said on MSNBC on Monday that the US expects Turkey to take action against Islamic State following the release of the hostages.Pentagon Spokesman John Kirby gave the same message to the Turkish daily Hurriyet, “But we know just by dint of geography that Turkey is, will be, and must be a partner in this effort.”“We know that Turkey has a significant national security interest in this. Every day they are dealing with over a million refugees. They have foreign fighters that they are concerned about on their borders and inside Turkey. We certainly expect that Turkey will contribute, one way or another,” he said.