Israel is intensifying military operations in one of the last Hamas strongholds in Gaza, as the sides stake out positions before ceasefire negotiations proposed by US President Donald Trump.

Hamas is seeking guarantees that a new U.S. ceasefire proposal for Gaza would lead to the war's end, a source close to the militant group said on Thursday, as medics said Israeli strikes across the territory had killed scores more people.

U.S. President Donald Trump says Israel has agreed on terms for a new 60-day ceasefire with Hamas and that Washington would work with both sides during that time to try to end more than 20 months of war in Gaza.