ISTANBUL — Turkey deployed 35 armored vehicles, including at least a dozen tanks, to the border with Syria on Monday as Islamist extremists closed in on the Syrian Kurdish border town of Kobane, raining shells from two directions.

At least two mortar rounds landed on the Turkish side of the border, but it was unclear whether Turkey would intervene to prevent the capture of the city, which was under heavy bombardment Monday night. At least 160,000 Syrian refugees, with more waiting to cross, have entered Turkey in the past week as the Islamic State, also known as ISIS, pushed toward the city.

“Maybe we can survive for a few days,” Idriss Nassan, the deputy foreign minister of the Kobane canton, told McClatchy, predicting “great resistance” by the city’s defender, a Kurdish militia called the People’s Protection Units. “But ISIS will reach the city of Kobane.”

Nassan said that at least 20 Islamic State shells had fallen Monday on Kobane, striking the city itself and every suburb, and killing at least three civilians. He said the extremists had been reinforcing their troops with new weapons and fighters. A fighter jet flew over the city for half an hour, he said, perhaps part of the U.S.-led coalition, but it didn’t carry out airstrikes.

“The coalition is bombing the Islamic State far away from Kobane, even as the same group is gathering its forces around Kobane,” said a Syrian rebel leader fighting with a group called the Brigade of Raqqa Revolutionaries east of Kobane. The rebel leader asked to be referred to only as Abu Issa – Issa’s father – for his security.

Anti-regime media activists said many fighters from both sides had been killed in the fighting over three villages outside Kobane.

The fighting at Kobane and the seeming reluctance of the international community to come to the aid of the People’s Protection Units reveals yet another layer of conflict that colors the conflict in Syria. Turkey, the United States and the European Union think the militia is itself a terrorist group, affiliated with the Kurdistan Workers Party. Some have accused it of collaborating with the Assad government, in part because it refused to allow rebel groups it considers radical Islamists to operate in Kurdish areas.

Suspicion runs in both directions. Nassan said the Democratic Union Party, which controls the canton, suspected that Turkey wanted to oust it from power and was using the Islamic State to accomplish this.

“The Turkish army is preparing for something, maybe to invade Kobane,” he said. He asserted that Turkey had pushed the Islamic State to attack Kobane and was planning to invade.

Turkey hasn’t stated its intentions, but President Recep Tayyip Erdogan has indicated that he won’t approve of any action that supports the People’s Protection Units.