An Israeli airstrike in southern Gaza killed a Hamas political leader, Salah al-Bardaweel, on Sunday, the militant group said, as Palestinian officials put the death toll from nearly 18 months of conflict at over 50,000.

Bardaweel was a member of the Hamas decision-making body, the political office, and had held posts such as heading the Hamas delegation for indirect truce talks with Israel in 2009.

"His blood, that of his wife and martyrs, will remain fuelling the battle of liberation and independence," the group said.

After two months of relative calm in the war, Gazans have again been fleeing for their lives after Israel effectively abandoned a ceasefire, launching a new all-out air and ground campaign on Tuesday against Hamas.

Explosions echoed throughout the north, central and southern Gaza Strip early on Sunday, as Israeli planes hit several targets in those areas in what witnesses said was an escalation of the attacks that began earlier in the week.

Israeli Prime Minister Benjamin Netanyahu has said the aim of the new campaign is to force the group to give up remaining hostages.

Israel launched its initial assault on Gaza after Hamas fighters stormed southern Israel on October 7, 2023, killing 1,200 people and taking more than 250 hostages, according to Israeli tallies.

Hamas has accused Israel of breaking the terms of the January ceasefire agreement by refusing to begin negotiations for an end to the war and a withdrawal of its troops from Gaza.

But Hamas has said it is still willing to negotiate and was studying "bridging" proposals from US President Donald Trump's special envoy, Steve Witkoff. (Reuters)