Boris Johnson has said the “price of freedom is worth paying” as he compared Russia with Nazi Germany.

The prime minister argued that Western allies must continue to back Ukraine because standing up against Vladimir Putin’s aggression would ultimately make the world a safer and more prosperous place.

Speaking at the G7 summit in Germany, Mr Johnson said that if Mr Putin is not resisted, it could give the green light to countries such as China to pursue their own goals of territorial expansion, he suggested.

Comparing the situation to the defeat of Nazi Germany, Mr Johnson declined to put a limit on UK support to Ukraine.

“The point I would make to people is, I think that sometimes the price of freedom is worth paying.

“And just remember, it took the democracies, in the middle of the last century, a long time to recognise that they had to resist tyranny and aggression.

“It took them a long time, it was very expensive.

“But what it bought in the end, with the defeat of the of the dictators, particularly of Nazi Germany, it bought decades and decades of stability, a world order that relied on a rules-based international system.

“And that is worth protecting, that is worth defending, that delivers long-term prosperity.”

Russia sanctioned 43 Canadian citizens on Monday, barring them from entering the country in a tit-for-tat response to Western sanctions on Moscow.

The list, published by the foreign ministry, included the chairperson of Canada’s governing Liberal Party, Suzanne Cowan, and the former governor of the Bank of England and Bank of Canada, Mark Carney.

In April, Moscow sanctioned 61 Canadian officials and journalists. It has barred dozens of other Western politicians, journalists and business figures from entering Russia.

Russia has defaulted on its foreign debts payment for the first time in years as its economy bleeds from the sanctions imposed by western nations in response to the invasion of Ukraine.

Moscow faced a Sunday deadline to pay off the interest worth about $100 million, originally due on 27 May, and meet a 30-day grace period. However the term expired without payment.

It is Russia’s latest economic collapse on the debt-front following a default on its domestic debts in 1998 and and after the 1917 Bolshevik Revolution where Moscow failed to pay off its international debts.

Ukrainian President Volodymyr Zelensky told leaders of the G7 that he wanted Russia’s war in Ukraine ended by the end of the year before the winter sets in, two European Union diplomats said.

Zelensky addressed the leaders of Britain, Canada, France, Germany, Italy, Japan and the United States by video link on Monday, the second day of the three-day G7 summit in southern Germany.

Ukrainian President Volodymyr Zelensky on Monday asked for anti-aircraft defence systems, more sanctions on Russia and security guarantees as he addressed leaders of the G7, a European official said.

Addressing the summit in the Bavarian Alps via video link, Zelensky also asked for help to export grain from Ukraine and for reconstruction aid, the European official said, speaking on condition of anonymity.

Boris Johnson and US president Joe Biden are at odds over a plane to cut the production of green fuels in a bid to free up land for food production.

The prime minister wants G7 leaders to temporarily cut the amount of grain produced for biofuels, claiming the process is pushing up the cost of food.

Britain is backed by Germany – also pushing for a temporary waiver on their biofuel commitments – but the US and Canada are against the move.

The US preparing to announce the purchase of an advanced surface-to-air missile system for Kyiv at the G7.

The pledge comes as the G7 leaders meet with talks by video link also scheduled with president Volodymyr Zelensky.

Biden is set to announce that the US is providing an advanced surface-to-air missile system to Ukraine, as well as additional artillery support, AP has reported, citing US official sources.

The US is understood to be purchasing Nasams, a Norwegian-developed anti-aircraft system, to provide medium- to long-range defence.

Nasams is the same system used by the US to protect the sensitive airspace around the White House and US Capitol in Washington.

Ukraine’s president Volodymyr Zelensky will urge leaders of some of the world’s richest countries to do more to support his nation’s fight against Russia.

Mr Zelensky will address Boris Johnson, Joe Biden and other G7 leaders by video link from Kyiv as his country continues to come under attack from Vladimir Putin’’ missiles.

In his nightly address on Sunday, he urged the allies to be “partners, not observers” and give his country the ability to defend itself – warning that any delay would be an invitation to Russia to strike again.Mr Zelensky said he would demand extra defence systems.

“We need a powerful air defence – modern, fully effective – which can ensure complete protection against these missiles,” he said.

He added: “Delays in the transfer of weapons to our state, any restrictions are actually an invitation for Russia to strike again and again.

“The occupiers – these terrorists – must be beaten with all our might so that they do not think they can put pressure and outplay someone.”

Boris Johnson’s government will pledge £10million to help rebuild Ukraine’s railways in a bid to use trains to export grain trapped by Vladimir Putin’s blockade in the Black Sea.

The prime minister is set to call on fellow leaders to take urgent action to get essential food supplies out of Ukraine at the G7 Summit in Germany on Monday.

Mr Johnson said the United Nations’ plan to get the grain out of Ukraine is a “non-starter” because Russia will continue to use food supply as a bargaining chip to ease sanctions.