BBC:
Hospital officials in northern Gaza say many people have been killed in overnight Israeli air strikes.
Gazan rescue teams say search operations began early in the morning after Israel bombed at least five buildings in Beit Lahia and Gaza City.
Hamas-aligned media say dozens of people were killed and many are still buried in the rubble – including women and children.
There was no immediate comment from the Israeli military. It has recently intensified its offensive in northern Gaza, saying it is stopping Hamas from regrouping.
Parts of northern Gaza are under Israeli siege and virtually no humanitarian aid has been delivered in 40 days, the UN warned earlier.