Israeli forces are stepping up their offensive in the southern Gaza Strip.

An expert says if the military finds and kills local Hamas leader Yahya Sinwar, the government may use his death to declare an end to the military operation.

Ronni Shaked of Hebrew University said if Sinwar is killed, "it will perhaps be much easier for the Israelis to say, 'We did it, we can now stop the war.'"

Sinwar is seen as the mastermind of the October 7 surprise attack that started the current conflict.

A senior Israeli official told local media on the weekend it is imperative for his country to kill Sinwar.

But Shaked said, in the longer term, Sinwar's death will not end the conflict, pointing to Israel's killing of other Hamas leaders in the past.

He said, "Hamas does not depend on one man. Hamas does not depend on some leaders -- Hamas is an ideology. In order to break the chain of wars, we need to change policy. We need to change the ethos of the two nations."

Meantime, several US media outlets say the Israeli military has started pumping seawater into the vast underground tunnel complex in the Gaza Strip.

A Japanese Middle East expert says the move may be an attempt to send a political message to Hamas -- indicating the government is ready to sacrifice the hostages that may still be held there.

Project Associate Professor Suzuki Hiroyuki of the University of Tokyo said, "I think Israel wanted to send a message that it is determined to destroy Hamas' last stronghold until it collapses. I think it shows its stance that Hamas and other Palestinian militant groups that took the hostages will bear the responsibility for what happens."

The move comes as US President Joe Biden warned Israel it is losing global support over the intense bombing in Gaza.

Suzuki said the US is concerned that the legitimacy of its partner's actions is being shaken. He believes Israel is starting to think about how to end the fighting.