A Kurdish Peshmerga soldier reaches out his hand to supporters in the northern Kurdish region of Iraq, Oct. 29.

DAMASCUS — The first group of Iraqi Kurdish Peshmerga fighters entered the besieged Syrian town of Kobani on Thursday to help push back “Islamic State” militants who have defied U.S. air strikes and threatened to massacre its Kurdish defenders.

Kobani, on the border with Turkey, has been encircled by the militants for more than 40 days. Weeks of U.S.-led air strikes have failed to break their stranglehold and Kurds are hoping the arrival of the Peshmerga will turn the tide.

The siege of Kobani has become a test of the U.S.-led coalition’s ability to stop Islamic State’s advance and Washington has welcomed the peshmerga’s deployment. It has intensified its air strikes in the past two days ahead of their arrival.

A first contingent of about 10 Peshmerga fighters arrived in Kobani from Turkey to prepare the way for a convoy equipped with heavy weapons, but gunfire and shelling by “Islamic State” fighters on the border area appeared to be causing delays.

Hemin Hawrami, a senior official in the Kurdistan Democratic Party in Iraq, wrote on Twitter that the Peshmerga already in Kobani were assessing where the heavy weapons would be deployed.

Around 100 Peshmerga fighters arrived by plane in southeastern Turkey on Wednesday, joined later that night by a land convoy of vehicles carrying arms including a cannon and truck-mounted machine guns.

In a compound protected by Turkish security forces near the border town of Suruc, the fighters were donning combat fatigues and preparing their weapons.

Syria condemned Turkey for allowing foreign fighters and “terrorists” to enter Syria in a violation of its sovereignty. Its foreign ministry described the move as a “disgraceful act.”

Turkey, which is a staunch backer of rebels fighting to oust Syrian President Bashar al-Assad, dismissed the comments.

“The Syrian regime has no legitimacy. Such statements from a regime that has lost its legitimacy are astonishing,” a senior Turkish government official said.

Around 200 Free Syrian Army (FSA) fighters have also entered Kobani from Turkey to support the fight against Islamic State, according to rebel commander Abdul Jabbar al-Oqaidi and a second Turkish government official.

Nizar Al Khateeb, commander of an FSA unit that has been fighting alongside the Kurds in Kobani, said the FSA, Peshmerga and Syrian Kurds would work from the same operations room and had no problem with the YPG, the main Syrian Kurdish armed group defending the town, leading the operation.

The FSA is a term covering dozens of armed groups fighting Assad but with little or no central command, and widely outgunned by Islamist insurgents elsewhere in the conflict.

Iraqi Kurdistan President Masoud Barzani said he was prepared to deploy more forces to Kobani if asked.

“Whenever the situation on the ground necessitates and more forces are requested from us and there is passage for them, we will send more forces to protect Kobani and defeat terrorists in Western Kurdistan,” he said.

The United States and its allies in the coalition have made clear they do not plan to send troops to fight “Islamic State” in Syria or Iraq, but they need fighters on the ground to capitalize on their air strikes.

Syrian Kurds have called for the international community to provide them with heavier weapons and munitions and they have received an air drop from the United States.

The Peshmerga were given a heroes’ welcome as their convoy of jeeps and flatbed trucks snaked its way for around 400 km (250 miles) through Turkey’s mainly Kurdish southeast on Wednesday.

U.S. Pentagon chief Chuck Hagel warned on Thursday that Syrian President Bashar al-Assad may “benefit” from U.S.-led airstrikes targeting the “Islamic State.” 

“As we and the coalition go after ISIL to help the Iraqis secure their government, but also the Middle East, yes, Assad derives some benefit of that, of course,” Hagel said.

However, he noted that Washington was pursuing a long-term strategy, which opposes any role for Assad in the future of Syria.

In New York, the new U.N. envoy on Syria said he is pursuing an “action plan” that involves freezing conflict in certain areas, possibly starting with Aleppo, to allow for humanitarian aid and local steps of a political process toward wider peace.

In his first briefing to the Security Council, Staffan de Mistura said the “horrific trigger” of ISIS’ recent onslaught in the north and east offers an opportunity for another approach to solving the conflict.