JERUSALEM, Nov 5 (Reuters) - Israeli Prime Minister Benjamin Netanyahu fired defence minister Yoav Gallant on Tuesday, saying he had no trust in him over the management of Israel's ongoing military operations as the wars in Gaza and Lebanon grind on.

Netanyahu appointed Foreign Minister Israel Katz, a close ally, to succeed Gallant, while Gideon Saar becomes the new foreign minister, Netanyahu's office said in a statement.

Gallant and Netanyahu, both in the right-wing Likud party, have clashed for months over the objectives of Israel's 13-month-old war in Gaza against the militant group Hamas, and many had expected the prime minister to sack him sooner or later.

But the timing was a surprise, and came as the United States was consumed by its presidential election. Gallant, who rose to the rank of general during a 35-year military career, had been a key interlocutor for Washington over the last year of conflict.

The shake-up comes as Israel's campaigns in both Gaza and Lebanon - where it is waging an offensive against the Iran-backed Hezbollah - have entered new phases, following the killing of both groups' top commanders. Israel is also bracing for Iran to respond to its Oct. 26 air strikes on the Islamic Republic.

Netanyahu said that beyond differing opinions, a "crisis of trust gradually opened ... and this crisis does not allow for the normal continuation of the management of the campaign.

"In light of this, I decided today to terminate the term of office of the Minister of Defence," he said in a statement.

Netanyahu added that he had tried to bridge the gaps but they "kept getting wider" and became public. "Worse than that, they came to the knowledge of the enemy and our enemies enjoyed it and derived a lot of benefit from it."

Netanyahu said such gaps were accompanied by statements and actions that "contradict the decisions of the government and the decisions of the cabinet."

In response, Gallant said: "The security of the state of Israel always was and will always remain my life's mission."

For months there had been open disagreements between Netanyahu and Gallant, reflecting a wider split between Israel's right-wing governing coalition and the military, which has long favoured reaching a deal to end the fighting and bring home scores of hostages held by Hamas.

Gallant said the war lacked clear direction, while Netanyahu reiterated that fighting could not cease until Hamas was wiped out as a governing entity and military force in Gaza.

Last year, shortly before the Gaza conflict erupted, Netanyahu had dismissed Gallant due to disagreements over the government's plans to overhaul Israel's judicial system, but after mass protests the prime minister reinstated him.

Itamar Ben-Gvir, a far-right minister in Netanyahu's coalition government, praised Tuesday's decision, saying Gallant was still "deeply trapped in the conception" that it "is not possible to achieve absolute victory".

But Benny Gantz, Netanyahu's main political rival, called the move "politics at the expense of national security."

Yair Lapid, another opposition leader, said the move "in the middle of the war is an act of madness", adding that Netanyahu was "selling out Israel's security and the soldiers of the IDF for his own political survival."

Photo from Reuters