DEIR AL-BALAH, Gaza Strip (AP) — At least 87 people are dead or missing after Israeli strikes on multiple homes in the northern Gaza Strip overnight and into Sunday, the territory's Health Ministry said.

It said another 40 people were wounded in the strikes on the town of Beit Lahiya, which was among the first targets of Israel’s ground invasion nearly a year ago.

There was no immediate comment on the strikes from the Israeli military, which said it was “continuing to operate across Gaza in both aerial strikes and ground operations.”

Israel has been carrying out a major operation in the urban Jabaliya refugee camp, also in northern Gaza, for the last two weeks. The military says it launched the operation against Hamas militants who had regrouped there.

The north has already suffered the heaviest destruction of the war, and has been encircled by Israeli forces since late last year, following the deadly Hamas' attack on Israel.

Israel ordered the entire population of the northern third of Gaza, including Gaza City, to evacuate to the south in the opening weeks of the war and reiterated those instructions earlier this month. Most of the population fled last year, but around 400,000 people are believed to have remained in the north.

Palestinians who fled the north at the start of the war have not been allowed to return.