SURUC, Turkey — A vanguard force of Iraqi peshmerga troops entered the embattled Syrian border town of Kobani from Turkey on Thursday, part of a larger group of 150 fighters that the Kurds hope will turn back an offensive by militants of the Islamic State group.

The deployment, accompanied by 50 members of the Free Syrian Army, was condemned by Syria’s government as an act of Turkish aggression and a “blatant violation of Syrian sovereignty.”

The first group of Kurdish fighters crossed into Syria following heavy overnight clashes as Islamic State extremists unsuccessfully tried to capture the frontier post, the only gateway in and out of the town.

Kobani is under attack by the militants from three sides despite weeks of airstrikes by a U.S.-led coalition.

Mustafa Bali, an activist based in the town, said the remaining troops will follow later in installments as a security precaution because the Islamic State fighters were targeting the border area.

“The first 10 are now with the People’s Protection Units and they include doctors and fighters and the rest are expected to enter in the coming hours at night,” Bali told The Associated Press. The People’s Protection Units, also known as the YPG, are the main force in predominantly Kurdish regions of northern Syria.

Other peshmerga forces were assembled in a facility on the outskirts of the Turkish border town of Suruc, about 71/2 miles from the Syrian frontier.

The Kurds have high expectations for the mission of the peshmerga troops, despite their low numbers. They are hoping that some of the more advanced weaponry they carry with them can help break a stalemate with the extremists, who outnumber and outgun the Kurds.

Activists say there are about 1,000 Syrian Kurdish fighters and more than 3,000 jihadis in the Kobani area. Most civilians fled in the first days of the Islamic State onslaught.

The ability of the small force to turn the tide of battle will depend on the effectiveness of their weapons and the continued bombardment from the coalition.

The coalition has carried out more than 150 airstrikes against the militants in and around Kobani, killing hundreds of them and helping stall their advance. But Syrian Kurds have pleaded for advanced weapons to help them gain the upper hand.