At least 73 Palestinians were killed and 99 injured in Israeli strikes on Gaza in the past 24 hours, the Gaza health ministry said in a statement on Monday.
Israel hit targets in south Gaza and across its border with Lebanon, the army said on Monday ahead of a visit by the top US diplomat who is seeking to avert a wider war.
Three months into its battle with Gaza-based Hamas, Israel's army says its focus has moved from the northern Gaza Strip to "dismantling" fighters in the centre and south of the Hamas-ruled Palestinian territory.
In the southern city of Khan Yunis, troops and warplanes overnight Sunday-Monday struck 30 targets which a military statement described as "significant." These included underground targets and weapons storage facilities, it said.
A drone also killed 10 fighters "preparing to launch rockets toward Israeli territory," the statement added. Also overnight, the military said it had hit "numerous Hezbollah targets" in Lebanon.
Israel and Lebanon's Iran-backed Hezbollah movement, a Hamas ally, have engaged in regular cross-border fire during the war that began an October 7 with Hamas's unprecedented resistance campaign against Israel.
But a strike last week in a Beirut stronghold of Hezbollah has been a major factor contributing to rising fears of spreading conflict.
A US Defense Department official has told AFP that Israel carried out the strike that killed Hamas's deputy leader Saleh al-Aruri.
Israel has responded with relentless bombardment and a ground invasion that have killed at least 23,084 people, most of them women and children, according to the Gaza health ministry.
On Monday, US Secretary of State Antony Blinken was holding talks on Gaza in the United Arab Emirates and Saudi Arabia before heading on to Israel, seeking to kick start concerted peace efforts that he says are needed to avoid a wider conflagration.