The Israel Defense Forces (IDF) said it was targeting what it called "terror targets" belonging to Hamas.

Israeli Prime Minister Benjamin Netanyahu and Defence Minister Israel Katz ordered the strikes on Tuesday morning, according to a statement from the PM's office.

"This follows Hamas's repeated refusal to release our hostages, as well as its rejection of all of the proposals it has received from US Presidential Envoy Steve Witkoff and from the mediators," it said.

"Israel will, from now on, act against Hamas with increasing military strength," it added.

The plan for the strikes "was presented by the IDF over the weekend and approved by the political leadership", it said.

Israel's Ambassador to the UN, Danny Danon, warned Hamas to release all the hostages, stating "we will show no mercy on our enemies".

Hamas has responded furiously, accusing Israel of treachery for overturning the ceasefire agreement. It also says Israel is exposing the remaining Israeli hostages held in Gaza to "an unknown fate".

But Hamas has not yet declared that it is resuming the war, instead calling on mediators and the United Nations to intervene.

Welcome to our live coverage of an overnight attack in the Gaza Strip, where the Israeli military says it has carried out "extensive strikes".

At least 220 people have been killed, the Hamas-run health ministry has said.

One of those reportedly killed was Mahmoud Abu Wafah, the highest-ranking Hamas security official in Gaza. But many civilians, including children, have also been caught up in the attack.

This is the largest wave of airstrikes in Gaza since the ceasefire began on 19 January. Talks to extend the Gaza ceasefire have failed to reach an agreement.

Stay with us while we keep you updated.