The brutal invasion of Israel by Hamas has triggered a prolonged war that is spreading across the Middle East. Here's what could happen next.

DEIR AL-BALAH, Gaza Strip — (AP) — An Israeli strike on a mosque in the Gaza Strip early Sunday killed at least 19 people, Palestinian officials said, as Israel intensified its bombardment of northern Gaza and southern Beirut in a widening war with Iran-allied militant groups across the region.

The strike in Gaza hit a mosque where displaced people were sheltering near the main hospital in the central town of Deir al-Balah. Another four people were killed in a strike on a school sheltering displaced people near the town.

Hamas launched a surprise attack into Israel almost exactly a year ago, killing 1,200 Israelis, taking 250 people hostage, and setting off a war with Israel that has shattered much of the Hamas-controlled Gaza Strip.

Tehran backs efforts for a ceasefire in Lebanon on the condition it would be backed by Hezbollah and simultaneous with a ceasefire in the Gaza Strip, Iran's foreign minister Abbas Araqchi said in Beirut on Friday.

Israel shifted some of its focus from Hamas to Hezbollah, which holds much of the power in parts of southern Lebanon and some other areas of the country.