Lebanese militant group Hezbollah fired a barrage of rockets towards Israel Thursday in retaliation for the killing of a senior commander amid growing fears of a new escalation in fighting on Lebanon’s southern border with Israel.

In one of the largest attacks in recent months, the Iran-backed militia said in a statement that it had fired over 200 rockets at several Israeli military facilities. In a separate statement late Wednesday, Hezbollah said it had fired over 100 rockets at bases near…