SURUC, Turkey — The United States and partner nations launched their first airstrikes against Islamic State militants in Syria, as fighting raged Monday between the extremist group and Kurdish forces near the border with Turkey, triggering a surge of tens of thousands of refugees.

The Pentagon said a mix of fighter jets, bombers and Tomahawk missiles fired from ships in the region targeted the Islamic State group. Pentagon press secretary Rear Adm. John Kirby said that because the military operation is ongoing, no details could be provided yet. He said the decision to strike was made early Monday by the military.

The strikes are part of the expanded military campaign that President Barack Obama authorized nearly two weeks ago in order to disrupt and destroy the Islamic State militants. The US has already launched 190 airstrikes on Islamic State targets in Iraq since an aerial campaign began Aug. 8.

As the fighting in Syria has moved closer to Turkey, the government is facing increasing pressure to step up efforts to take on the Islamic State extremists.

Turkey is resisting because it fears that arming Kurdish men to fight the group could complicate peace talks with Turkish insurgents within its own borders.

The Islamic State group’s offensive against the Syrian city of Kobani, a few miles from the border, has sent 130,000 refugees to seek safety in Turkey in the last few days. The conflict in Syria had already led to more than 1 million people flooding over the border in the past 3½ years.

But in addition to the refugee crisis, hundreds of Kurds in and around this city near the frontier have clashed with Turkish police, who fired tear gas and water cannons. The Kurds say Turkey is hampering their efforts to let them cross into Syria and help their brethren.

An 18-year-old Turkish citizen in Suruc said he wanted to join the Kurdish fighters in Syria. He identified himself only by his first name, Azam, for fear of reprisal from authorities.

“The Islamic State is on the other side of the border and moving freely, slaughtering people, but they are just sitting and watching,” he said of the Turkish authorities.

“If I get a chance to get a weapon, I’ll go to help our brothers by end of the day,” he said. “Kobani is our land, too, and people there are our people.”

Syrian Kurdish fighters were crossing back and forth over the border, while other Syrian Kurds were seen selling livestock to raise money for weapons.

Not far away on the border, the black flag of the Islamic State could be seen flying in a captured Syrian village along with the smoke from mortar fire.

Spillover from Syria poses a problem for Turkey. The only local fighters capable of resisting the Islamic State group are Syrian Kurds aligned with the Kurdistan Workers’ Party, or PKK, which has fought a three-decade insurgency in southeastern Turkey.

Turkish officials have said PKK militants from Turkey are streaming to Syria to join the fight. The conflict in Syria already is inflaming tensions with Turkish Kurds and could undermine peace talks with the PKK. Turkey’s ambivalence about the fight between Kurds and the Islamic State group, which could leave the PKK either drained or emboldened, could further complicate its participation in a US-led coalition against the Islamic State group.

While joining the coalition, Turkey had declined to take part in combat, citing the Turkish hostages held by the Islamic State in Mosul, Iraq. But even after the 46 Turks and three Iraqis were freed, Turkey has not changed its stance.

Turkish government officials have not revealed how they managed to secure the release of the captives. President Recep Tayyip Erdogan denied paying a ransom but has been vague on whether there was a prisoner swap.

Erdogan indicated for the first time Monday that his country may have traded Islamic State members it held captive in exchange for the Turkish hostages held by the militants.

Asked about it in New York on Monday, Erdogan said “such things may be possible.” He said Israel released 1,500 Palestinian prisoners in exchange for one Israeli hostage. “So you see, it’s possible,” he added.

Speaking at the Council of Foreign Relations in New York, Erdogan tried to sidestep the question.

“This process that took 102 days involved an operation by the national intelligence agency … it was a historic, very important process,” he said.

US Secretary of State John Kerry said Washington now expects Turkey to step up in the fight against the militants.

Erdogan has said Turkey will discuss its participation in the coalition during this month’s UN General Assembly. The US ally and member of the NATO military alliance has made commitments of only limited help in the fight against the Islamic State, which has seized large parts of Syria and Iraq and rules by its harsh version of Islamic law.

The US is looking for major participation from nations in the region in the campaign to destroy the Islamic State. Obama has pledged that no American troops will be involved in combat missions against the group, and the US expects nations in the region to provide those.

The Islamic State released a new audio recording online late Sunday in which a spokesman urged Muslims worldwide to kill civilians of those nations that join the fight. A French citizen was kidnapped in Algeria by an al Qaeda splinter group that said it will kill him unless France ends its participation in airstrikes against the Islamic State in Iraq, officials said.

Army Gen. Martin Dempsey, chairman of the US Joint Chiefs of Staff, said Monday he remained hopeful that Turkey would participate in the coalition.

“We need Turkey, frankly,” he said during a visit to Croatia, because of its military capability, regional influence and political gravitas in the Muslim world.

But Turkey may also have questions for the US, if the support that Washington gives to Kurds in Iraq is extended to the Kurds fighting in Syria. Iraqi Kurdish peshmerga fighters are already starting to get training from Iraq’s Western allies in fighting the Islamic State.

“The US says it will make sure that arms won’t go to the PKK, but this isn’t possible,” said Hasan Koni, a professor of international law at Istanbul’s Kultur University. He added that the tensions have brought the peace process to its most difficult phase as Kurds question Turkey’s ambivalent stance in their fight in Syria and Iraq.

“The Kurds could say: ‘What kind of a peace is this? We are being strung along,'” he said.

Turkish authorities may have concerns that Turkey’s Kurds, bolstered by Western arms and emboldened by battlefield success, could harden their demands on the government in Ankara.

Beyond the political questions, the conflict is adding to a huge burden for Turkey. On Monday, Deputy Prime Minister Numan Kurtulmus warned that the number of Syrians crossing the border could rise further to “a refugee wave that can be expressed by hundreds of thousands.”

“This is not a natural disaster. … What we are faced with is a manmade disaster,” Kurtulmus said of the surge of mostly women, children and the elderly that started late Thursday.