A former Israeli prime minister who served briefly as a mediator at the start of Russia's war with Ukraine says he drew a promise from the Russian president not to kill his Ukrainian counterpart.

Former Prime Minister Naftali Bennett emerged as an unlikely intermediary in the war's first weeks, becoming one of the few Western leaders to meet President Vladimir Putin during the war in a snap trip to Moscow last March.

While Bennett's mediation efforts appear to have done little to end the bloodshed that continues until today, his remarks, in an interview posted online late Saturday, shed light on the backroom diplomacy and urgent efforts that were underway to try to bring the conflict to a speedy conclusion in its early days.

In the five-hour interview, which touched on numerous other subjects, Bennett says he asked Putin about whether he intended to kill Ukrainian President Volodymyr Zelenskyy.

“I asked ‘what’s with this? Are you planning to kill Zelenskyy?’ He said ‘I won’t kill Zelenskyy.’ I then said to him ‘I have to understand that you’re giving me your word that you won’t kill Zelenskyy.’ He said ‘I’m not going to kill Zelenskyy.’”

Bennett said he then called Zelenskyy to inform him of Putin's pledge.

“'Listen, I came out of a meeting, he’s not going to kill you.’ He asks, ‘are you sure?’ I said ’100% he won’t kill you.’"

Bennett said that during his mediation, Putin dropped his vow to seek Ukraine's disarmament and Zelenskyy promised not to join NATO.

There was no immediate response from the Kremlin, which has previously denied Ukrainian claims that Russia intended to assassinate Zelenskyy.

Bennett, a largely untested leader who had served as prime minister for just over six months when the war broke out, unexpectedly thrust himself into international diplomacy after he had positioned Israel into an uncomfortable middle ground between Russia and Ukraine. Israel views its good ties with the Kremlin as strategic in the face of threats from Iran but it aligns itself with Western nations and also seeks to show support for Ukraine.

An observant Jew and little known internationally, he flew to Moscow for his meeting with Putin during the Jewish Sabbath, breaking his religious commitments and putting himself at the forefront of global efforts to halt the war.

But his peacemaking efforts did not appear to take off and his time in power was short-lived. Bennett's government, an ideologically diverse union that sent current Prime Minister Benjamin Netanyahu into a brief political exile, collapsed in the summer over infighting. Bennett stepped away from politics and is now a private citizen.

(AP)

Israeli Prime Minister Naftali Bennett

Former Israeli PM: Putin promised not to kill Zelenskyy