Ukraine’s Jewish leaders are preparing to lead the fight if the country is invaded.

Gennadiy Korban, a multi-millionaire businessman and the deputy head of Dnepropetrovsk, Ukraine’s second largest city, this week gathered national commanders to prepare a defensive plan, including how and where military resources should be deployed.

One of the country’s leading businessmen, billionaire Gennady Bogolyubov, has signed a document saying that he will personally take up arms against Russia.

Another Dnepropetrovsk businessman and community leader, Igor Kolomoisky, returned to his home city two weeks ago in a new role as regional governor.

On Monday Mr Kolomoisky announced a $25 million donation to the Ukrainian army’s southern command to pay for fuel for military vehicles and aircraft.

Following the annexation of the Crimea earlier this month, Nato commanders have issued two warnings about the Russian forces gathering along Ukraine’s eastern border. This week the US threatened to ratchet up sanctions against Moscow should it push any deeper into the country.

However, Mr Korban, a major donor to the Ukrainian Jewish community, said he had little confidence that Ukraine would receive any external military assistance and stressed the need for all citizens to unite.

“We are ready to fight. I invited all the heads of the military and emergency forces to join me to prepare a plan in case of invasion.”

He said that Dnepropetrovsk, home to the country’s largest and most influential Jewish community, would be a prime target for Russia.

The city’s armaments industry, its position as the region’s economic hub and its situation on the Dneper river — a natural border between east and west Ukraine — make it far more important to Mr Putin than regions further east, he said.

“Dnepropetrovsk is a far bigger target than Crimea — it will be the centre of a buffer zone that can stand between western Ukraine and Russian-speaking Ukraine.”

Members of the 50,000-strong Jewish community in Dnepropetrovsk have been in discussions over whether to form Jewish brigades within the force being organised by Mr Korban or to sign up to the army individually.

Dnepropetrovsk Chief Rabbi Shmuel Kaminezki said: “People are saying we must not let this situation be a replay of the Second World War. Then, Jews thought that the Germans had benign intentions because of their experiences of the First World War. On Simchat Torah in 1941, 11,500 Jews were marched to a park and shot dead.”

Oleg Rostovtsev, head of press for the Menorah Centre, Dnepropetrovsk’s vast Jewish community centre set up by Mr Bogolyubov, said: “This is our country, our community, our city. Jews are part of Ukraine’s political nation. Some Israeli citizens who served in the IDF have already come back to offer their services to the Ukrainian army and others are planning to do so,” he said.

There is widespread anger among Dnepropetrovsk’s Jewish leaders over Mr Putin’s claims that Ukrainian ultra-nationalists have systematically targeted Jews following the revolution.

Rabbi Kaminezki said: “What Putin is saying about antisemitism in the Ukraine is mostly just a lie to divide us. We Jews are fighting as Ukrainians, for freedom for all our country.”

US Under Secretary of State for Political Affairs Wendy Sherman, who is Jewish and has Ukrainian roots, visited the Dnepropetrovsk community and the Menorah Centre last Friday. Community executive director Zelig Brez said that she was “shocked” to find that Jews live openly and are very well integrated into the city, with very little antisemitism, and that she found life was “nothing like the headlines” in the Russian media.