There was no claim of responsibility for the early morning attack. The military said Hamas fired the rocket from about 120 km (75 miles) away, making it the longest-range attack from Gaza causing casualties since a 2014 war.
The Palestinians are seeking to press war crimes charges against Israel at the International Criminal Court in The Hague. The court’s prosecutor has opened a preliminary investigation, but not made a decision on whether to move ahead with a case.
Home to 2 million Palestinians, more than half of them war refugees and their descendents, Gaza has suffered deep poverty and infrastructure collapses under a 12-year blockade by Israel and Egypt, which say they aim to curb Hamas threats.
Israel's deadly tactics in confronting the weekly Friday protests have drawn international condemnation. But support has come from its main ally, the United States, which like Israel, has cast blame on Hamas.