The brother of an Israeli-Ukranian sailor taken hostage by Russian soldiers in the Black Sea has spoken of his terror that he may be executed.

Yuri Shvidky, 51, a father of two, was travelling aboard the Princess Nicole vessel when it was seized by Russian warships at the weekend.

His brother, Semion, told Ynet: “My brother texted us that he has been detained by the Russians, that he was taken to land, and he has no clue where he is. He hasn’t written to us since.”

He added: “I am worried sick because the Russians are shooting people and we don’t know what may happen to him.”

Another Israeli, Roman Brodsky, was shot dead last weekend at a Ukrainian army checkpoint near Kyiv when soldiers mistakenly believed he was a Chechen militant.

A DJ with Ukrainian heritage, he had been travelling in Moldova-bound convoy in an effort to reach Israel.

Israeli PM Naftali Bennett said: “I would like to send my condolences to the wife, children and family of the late Roman, in Israel and in Ukraine.

Mr Brodsky’s desperate parents appealed for help returning his son’s remains from Ukraine for burial in Israel.

Attacking “dictator” Putin over their son’s death, his father said: “He is left there alone and I do not know where he is.”

Channel 12 reported on Monday that Mr Brodsky’s partner, Mila, remains in Ukraine and fears she may not get out alive. “They are shooting like crazy,” she reportedly said.

Demonstrators outside Russia’s embassy in Tel Aviv last Saturday set their Russian passports on fire, with some chanting: “Putin is a murderer.”

Russian-speakers make up 15 per cent of Israel’s population.

Many of the protesters were born in Ukraine or have family there. But there were also Russian citizens appalled at the actions of Putin’s regime.

Israel is sending 100 tons of humanitarian aid to Ukraine to provide relief for civilians.

Mr Bennett spoke to Vladimir Putin on Sunday, offering to serve as an intermediary in the talks between Russia and Ukraine, according to the Jerusalem Post.

Negotiating groups from the two governments arrived in Belarus on Monday and began discussions, but Ukraine’s Jewish president Volodomyr Zelensky said he was not optimistic about the outcome.

A Kremlin delegation was due to arrive for a second round of discussions in Belarus on Wednesday evening.

On Monday Israel voted in favour of the United Nations General Assembly resolution condemning the Russian invasion of Ukraine, days after Jerusalem refused to co-sponsor a similar measure in the Security Council.