MOSCOW — At least four police officers were injured on Monday in a series of attacks in the mountain republic of Chechnya, Russian law enforcement authorities said, raising fears of renewed violence in the restive region.

Three attacks occurred around the same time in different locations, the Investigative Committee, a Russian security agency, said in a statement: an assault outside a police station by two men armed with knives, an attempted suicide bombing and the running over of two officers with a vehicle in Grozny, the regional capital. No police officers were reported killed.

The Islamic State group’s official news agency claimed responsibility in a statement on the Telegram messaging app, describing the assailants as “fighters from the Islamic State.” It did not use the phrasing typically employed to describe an inspired attack, suggesting that it viewed those who carried out the violence as core members.

That represents an embarrassment to Ramzan A. Kadyrov, the strongman who rules Chechnya. The republic is formally a part of the Russian Federation, but the Kremlin, which has fought two brutal wars against a separatist insurgency there over the past three decades, gives Mr. Kadyrov a high degree of autonomy to crush dissent.