SURUC, Turkey — Some 130,000 Syrian refugees fleeing the advance of Islamic State militants have crossed the border into Turkey in the past four days, Turkey's deputy prime minister said Monday, warning that the number could rise further as the militants continue their onslaught.
Numan Kurtulmus warned that the number could rise to "a refugee wave that can be expressed by hundreds of thousands."
The refugees have been flooding into Turkey since Thursday, escaping an Islamic State offensive that has pushed the conflict nearly within sight of the Turkish border. The conflict in Syria had already pushed more than a million people over the border in the past 3½ years.
"This is not a natural disaster... What we are faced with is a man-made disaster," said Kurtulmus, adding that Turkey was taking measures to prepare.
"We don't know how many more villages may be raided, how many more people may be forced to seek refuge. We don't know," he added. "An uncontrollable force at the other side of the border is attacking civilians. The extent of the disaster is worse than a natural disaster."
The situation has raised tensions between Turkish authorities and Kurds who claim that the government is hampering their efforts to provide help to their brethren in Syria.
New clashes erupted along the border gate, near the town of Suruc, on Monday with police firing tear gas and water cannons to disperse Kurds protesting the government or demanding to reach Syria.
Suruc itself was flooded with refugees and armored military vehicles.
The al-Qaida breakaway group — which says it has established an Islamic state, or caliphate, ruled by a harsh version of Islamic law in territory it captured straddling the Syria-Iraq border — has in recent days advanced into Kurdish regions of Syria that border Turkey, where fleeing refugees on Sunday reported atrocities that included stonings, beheadings and the torching of homes.
On Saturday, Turkey secured the release of 49 hostages who were held by the group for more than three months and U.S. Secretary of State John Kerry said Monday that the United States now expects Turkey to step up in the fight against the militants.
Turkey had previously been reluctant to take part in international efforts against the group, citing the safety of its citizens who were captured when the group overran the Iraqi city of Mosul in June.
Turkish officials have refused to reveal how Ankara managed to secure the release of the hostages. President Recep Tayyip Erdogan has denied paying a ransom but has been vague on whether there was a prisoner swap.
On Monday, fighting between Kurdish fighters and the militants raged on near the northern city of Kobani, which is also known as Ayn Arab, the Britain-based Syrian Observatory for Human Rights said.
The Observatory said the militants have lost at least 21 fighters since Sunday night, most of them on the southern outskirts of Kobani.
Nawaf Khalil, a spokesman for Syria's Kurdish Democratic Union Party, or PYD, told The Associated Press that the situation on the ground "is better than before."
He added that the main Kurdish force in Syria, known as the People's Protection Units, had pushed Islamic State fighters about 10 kilometers (6 miles) away from their previous positions east of Kobani.
"We will fight until the last gunman in Kobani," Khalil said.
Suzan Fraser in Ankara, Turkey, and Bassem Mroue in Beirut contributed.