A senior US government official has referred to progress in talks for a ceasefire agreement in Gaza, but said it will take some time to finalize a deal.

Negotiations for a ceasefire between Israel and Hamas, as well as the release of hostages have been ongoing under the mediation of Qatar and others.

The three-stage plan now being discussed begins with a temporary ceasefire in phase one and is followed by the permanent end to fighting in phase two. The final stage would encompass the reconstruction of Gaza.

The senior US official said on Thursday that a breakthrough has been achieved over a "stumbling block" in the transition from phase one to phase two.

The official also stressed that there is still some work to do.

Israel says it will send a delegation led by its intelligence chief to Qatar as early as on Friday.

Israel maintains that it will not end the fighting until it destroys Hamas. The Islamic group wants a permanent ceasefire and the withdrawal of Israeli troops from Gaza.

Israeli forces continued their offensive in the north and south of Gaza on Friday. Palestinian media say four people were killed when a house was bombed in Gaza City.

Health officials in Gaza say 38,011 people have been killed since the conflict began last October.