COLUMBUS, Ohio — The Islamic State claimed responsibility on Tuesday for the attack at Ohio State University, calling the student who drove his car into pedestrians and then slashed people with a butcher knife a “soldier” of the terrorist group.

A day after the assault injured 11 people, local and federal law enforcement agencies were searching for evidence to determine whether it was an act of terrorism and whether the assailant acted alone, while the large Somali immigrant community here denounced the attack and braced for a possible backlash.

The attacker, identified as Abdul Razak Ali Artan, a Somali-born Ohio State student, was shot and killed by a police officer.

The Islamic State, which has urged Muslims to carry out attacks in the West, released a one-paragraph statement on its news wire, via the messaging app Telegram, that included the same stock phrases it has used in previous claims. Although there was no immediate evidence that Mr. Artan had declared allegiance to any terrorist group or claimed allegiance to one, the vast majority of attacks claimed this way by the Islamic State have eventually been shown to at least have been inspired by the group’s propaganda.