The leader of the main Syrian Kurdish political party is in Turkey for secret talks with intelligence officials as the battle rages with jihadists for the Syrian town of Kobane, Turkish media said Sunday.

The leader of the Democratic Union Party (PYD) Salih Muslim held talks with officials from Turkey's intelligence agency, the National Intelligence Organisation (MIT), in Ankara on Saturday, the Hurriyet daily reported, quoting security sources.

A mortar that crashed into a house on Turkish territory just a few kilometers from a border area inside Syria where Kurdish fighters are battling Islamic State (IS) jihadists wounded five people on Sunday, medical sources said.

The mortar -- whose origin was not immediately clear -- smashed into the house two kilometers (1.2 miles) from the Syria border outside the town of Suruc, medical sources told Agence France Presse.

Smoke billowed over the key Syrian border town of Kobane on Sunday as Kurdish fighters supported by U.S.-led air strikes battled to hold back intensified attacks by Islamic State jihadists.

IS fighters seized part of a strategic hill overlooking the town late on Saturday, a monitor said, but their progress was slowed by new strikes from the coalition of Washington and Arab allies.

The United Arab Emirates has expressed surprise after U.S. Vice President Joe Biden suggested the Gulf state had armed and financed jihadists in Syria, along with other regional powers.

Biden's remarks were "amazing and ignore the role of the Emirates in the fight against extremism and terrorism," the UAE minister of state for foreign affairs, Anwar Mohammad Gargash, said in a statement carried late Saturday by the official WAM news agency.

United States Vice President Joe Biden on Saturday apologized to Turkish President Recep Tayyip Erdogan over comments suggesting that Ankara and other regional powers had financed and armed jihadist organizations in Syria.

Erdogan reacted furiously earlier Saturday at comments made by Biden at Harvard University on Thursday, in which the vice president criticized allies in Turkey and the Arab world for supporting Sunni militant groups in Syria such as the Islamic State (IS) group and al-Qaida-linked Al-Nusra.

Turkey warned on Saturday it would not hesitate to strike back at Islamic State jihadists if they attacked Turkish troops stationed at Ankara's exclave inside Syria.

"We will absolutely not hesitate to respond if something happens there," President Recep Tayyip Erdogan told reporters in Istanbul, referring to the tomb of Suleyman Shah, the grandfather of the founder of the Ottoman dynasty Osman I.

At least 35 jihadists from the Islamic State group were killed in air strikes by a U.S.-led coalition overnight in northern and northeastern Syria, a monitor said Saturday.

The Syrian Observatory for Human Rights said 30 jihadists were killed around the town of Shadadi in northeastern Hasakeh, and another five outside the embattled town of Kobane, on the border with Turkey in northern Aleppo province.

Turkish President Recep Tayyip Erdogan, known for his suspicion of new technology, declared he was "increasingly against the Internet every day" as he defended curbs on online freedoms, a journalists' rights group who met him said Friday.

However the presidency denied Erdogan was "anti-Internet", saying that he just wanted to raise the alarm over the use of the Internet by extremists.

The Syrian government said Friday any Turkish military intervention on its soil would be considered an act of aggression, and urged the U.N. Security Council to prevent any such action by Ankara.

A day after Turkey's parliament authorized military action against the Islamic State (IS) group in Syria and Iraq, the foreign ministry said the "declared policy of the Turkish government represents a real aggression against a member state of the United Nations."

Turkey will do whatever it can to prevent the Syrian Kurdish town of Kobane falling to jihadists, Prime Minister Ahmet Davutoglu said after the Turkish parliament gave the green light for military action.

Islamic State (IS) militants have now advanced to a few kilometers from Kobane, known as Ain al-Arab in Arabic, which lies just across the Turkish border. Turkey is hosting tens of thousands off refugees from the region.