By Daren Butler

SURUC Turkey (Reuters) - About 60,000 Syrian Kurds fled into Turkey in the space of 24 hours, a deputy prime minister said on Saturday, as Islamic State militants seized dozens of villages close to the border.

Turkey opened a stretch of the frontier on Friday after Kurdish civilians fled their homes, fearing an imminent attack on the border town of Ayn al-Arab, also known as Kobani. A Kurdish commander on the ground said Islamic State had advanced to within 15 km (9 miles) of the town.

Local Kurds said they feared a massacre in Kobani, whose strategic location has been blocking the radical Sunni Muslim militants from consolidating their gains across northern Syria.

The United States has said it is prepared to carry out airstrikes in Syria to stop the advances of Islamic State, which has also seized tracts of territory in neighbouring Iraq and has proclaimed a caliphate in the heart of the Middle East.

U.S. forces have bombed the group in Iraq at the request of the government, but it is unclear when or where any military action might take place in Syria, whose president, Bashar al-Assad, Washington says is no longer legitimate.

Lokman Isa, a 34-year-old farmer, said he had fled with his family and about 30 other families after heavily armed Islamic State militants entered his village of Celebi. He said the Kurdish forces battling them had only light weapons.

"They (Islamic State) have destroyed every place they have gone to. We saw what they did in Iraq -- in Sinjar -- and we fled in fear," he told Reuters in the Turkish town of Suruc, where Turkish authorities were setting up a camp.

Sitting in a field after just crossing the border, Abdullah Shiran, a 24-year-old engineer, recounted scenes of horror in his village of Shiran, about 10 km (six miles) from Kobani.

"IS came and attacked and we left with the women but the rest of the men stayed behind ... They killed many people in the villages, cutting their throats. We were terrified that they would cut our throats too," he said.

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HUDDLING IN FIELDS

Turkish soldiers looked on as the refugees, many of them women carrying bundles on their heads, streamed across. Hundreds of people huddled in the dusty fields with their few belongings.

Turkish Deputy Prime Minister Numan Kurtulmus put the number of Syrian Kurds to have crossed the 30-km section of the border that has been open since Friday at 60,000. Officials said many thousands were still waiting to cross on Saturday evening.

"The United States, Turkey, Russia, friendly countries must help us. They must bomb Islamic State. All they can do is cut off heads, they have nothing to do with Islam," said Mustafa Saleh, a 30-year-old water industry worker.

"I would have fought to my last drop of blood against Islamic State, but I had to bring the women and children."

Kurdish forces have evacuated at least 100 villages on the Syrian side since the militants' onslaught started on Tuesday.

"Islamic State sees Kobani like a lump in the body, they think it is in their way," said Rami Abdulrahman, who runs the Syrian Observatory for Human Rights, which monitors Syria's civil war.

Islamic State has executed at least 11 Kurdish civilians, including boys, in the villages it has seized near Kobani, the Observatory said.

Abdulrahman said more than 300 Kurdish fighters had crossed into Syria from Turkey late on Friday to help push back Islamic State, but that it was not clear which group they belonged to.

"Islamic State is killing any civilian it finds in a village," Mustefa Ebdi, director of a local radio station called Arta FM, told Reuters by telephone from the northern outskirts of Kobani. He said he could see thousands of people waiting to cross the border into Turkey.

"People prefer to flee rather than remain and die," he said. "(Islamic State wants) to eliminate anything that is Kurdish. This is creating a state of terror."

On his Facebook page, Ebdi said the killing of 34 civilians - women, elderly, children and the disabled - had been documented. He said the residents of 200 villages had been forced to flee.

CLOSING IN

Scrambling to coordinate aid, the mayor of Suruc, Orhan Sansal, described the situation in the area as "chaotic".

"Help is coming but there are problems with accommodation. Some people are staying with relatives, some in wedding halls, some in mosques and municipal buildings," he said.

Esmat al-Sheikh, commander of the Kurdish forces defending Kobani, told Reuters by telephone that clashes were occurring to the north and east on Saturday.

He said Islamic State fighters using rockets, artillery, tanks and armoured vehicles had advanced towards Kobani overnight and were now only 15 km away.

At least 18 Islamic State fighters were killed in clashes with Syrian Kurds overnight as the militant group took control of more villages around the town, according to the Observatory.

Iraqi Kurdish leader Masoud Barzani called on Friday for international intervention to protect Kobani from the Islamic State advance, saying the insurgents must be "hit and destroyed wherever they are".

Western states have increased contact with the main Syrian Kurdish political party, the PYD, whose armed wing is the YPG, since Islamic State made a lightning advance across northern Iraq in June.

The YPG says it has 50,000 fighters and should be a natural partner in the coalition the United States is trying to build.

But such cooperation could prove difficult because of Syrian Kurds' ties to the Kurdistan Workers' Party (PKK), a group listed as a terrorist organisation by many Western states due to the militant campaign it has waged for Kurdish rights in Turkey.

The PKK on Thursday called on young men in Turkey's mainly Kurdish southeast to join the fight against Islamic State. On Saturday Kobani's local radio station broadcast a call to arms from PKK commander Murat Karayilan in Kurdish.

(Additional reporting by Asli Kandemir in Istanbul, Sylvia Westall and Tom Perry in Beirut,; Writing by Seda Sezer and Sylvia Westall; Editing by Gareth Jones and Kevin Liffey)