TEL AVIV, Israel—An assailant killed four people and seriously injured two others in southern Israel Tuesday, stabbing several people and ramming his car into a cyclist in one of the deadliest suspected terrorist attacks against Israelis in recent years.

The assailant, who was identified as an Arab Bedouin in his 30s from a town in southern Israel, was known to security services, Israeli police said. A security official said the assailant had been imprisoned in 2015 for supporting Islamic State, and was arrested before trying to join the Islamist militant group in Syria.

“To the best of our knowledge, he operated alone,” Israel’s police commissioner Kobi Shabtai said in televised media statement. He described the incident as a terrorist attack but didn’t explain the attacker’s motivation.

The attack comes at a time of increasing tension between Israelis and Palestinians in the West Bank and Jerusalem. As the Muslim holy month of Ramadan approaches, Israeli security services are worried about the possibility of a larger escalation. Palestinian assailants also carried out stabbings in Jerusalem on Saturday against a civilian jogger, and again on Sunday against two policemen, though neither incident resulted in fatal injuries.

Tension also has risen between Bedouin communities and Israeli authorities in the Negev Desert, where land and building disputes are frequent.

The assailant first stabbed and killed a woman at a gas station in the southern Israeli city of Beersheba, according to the police. He then got in his car and rammed a cyclist before driving to a shopping center and stabbing several other people. The assailant was shot by a bystander and killed, said police.

Israeli paramedics said one victim, a woman, was pronounced dead on the scene while three were later pronounced dead from their injuries while being treated in a hospital.

The attack was praised by the Palestinian militant group Hamas, which controls the Gaza Strip, but it didn’t claim responsibility.