KIRYAT SHMONA, Israel—Israeli authorities ordered the evacuation of this city close to the Lebanese border, reflecting Israel’s growing concern that a second front could open up to the north as it continues its bombing campaign in Gaza, including a strike on a church compound overnight.

Israel on Friday also released more details about the hostages captured during the Oct. 7 attack by Hamas—saying most of them are alive—as it laid out plans that include a ground invasion to eliminate the group, designated as a terrorist organization by the U.S., as a political and military force in the Gaza Strip.