Israel has confirmed it carried out “extensive strikes” in Gaza overnight following two months of ceasefire in the war-torn region.

The Hamas-run health ministry said at least 400 people have been killed, including the highest-ranking Hamas security official in Gaza, Mahmoud Abu Wafah.

The AFP news agency has quoted the head of the Gaza health ministry, Mohammed Zaqut, who said most of the dead are women and children.

It was the largest wave of attacks on Gaza since the temporary truce, a deal set up by former US president Joe Biden’s team and pushed over the line by Donald Trump’s Middle East envoy, began on January 19.

The war stretches back to October 2023 when Hamas militants killed 1,200 people on Israeli soil and took a further 250 hostage.

Israel then declared war on Hamas. Approximately 48,000 Palestinians have been killed since, according to Hamas authorities in Gaza.

The officials have accused Israel of unilaterally breaking the ceasefire, while Israel claims it attacked after a lack of progress in talks to extend the very fragile peace.

The Israel Defence Forces (IDF) also claim it was aiming at “terror targets” overnight.

A statement from Israeli PM Benjamin Netanyahu’s office said: “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.

“Israel will, from now on, act against Hamas with increasing military strength.”

It added that the plan for the strikes “was presented by the IDF over the weekend and approved by the political leadership”.

Hamas has not said it wants to resumes the war but has accused Israel of treachery and said it was exposing the remaining 59 Israeli hostages in Gaza to an “unknown fate”.

The White House said it had been warned in advanced and voiced support for the action.

Israel has ordered Gaza civilians to evacuate from some areas of the Palestinian territory, possibly suggesting further attacks are coming.

UK cabinet office minister Pat McFadden responded to the strikes this morning, telling Sky News: “From the point of view of the government, we will use whatever diplomatic influence we have to try to get that ceasefire restored as soon as possible.”

Asked if the UK is now “irrelevant” in this conflict because it was not warned ahead of the strikes, he said: “I don’t believe that’s the case. I think the UK has diplomatic influence, obviously we work with allies to try to exercise that influence. I still think the UK’s diplomatic voice matters in the world.”

Foreign secretary David Lammy also criticised Israel on Monday for blocking humanitarian aid into Gaza over the last fortnight, saying it was a breach of international law – the first time a government figure has made such an accusation against Israel.