A Labour government would have an “ironclad commitment” to backing Ukraine against the Russian invasion, two shadow ministers have promised.

David Lammy and John Healey visited Kyiv on Monday to stress the party “fully backs” Britain’s increased military aid for the war-torn country as Moscow intensifies its attack in Kharkiv.

European security will be a Labour government’s “first foreign and defence priority” and there would be “no change” in the support offered to Ukraine, they said.

Labour’s action plan lays out a wide-ranging approach to stand with Ukraine, confront Russian aggression and pursue Putin for his war crimes. We will stand with Ukraine until it wins

It comes after Prime Minister Rishi Sunak claimed giving Sir Keir Starmer the keys to No 10 would leave the country less safe and embolden Russian President Vladimir Putin.

Mr Lammy and Mr Healey met head of the Ukrainian president’s office Andriy Yermak and defence minister Rustem Umerov on Monday as they pledged to stand with Ukraine for “as long as it takes”.

In a joint statement, the shadow foreign secretary and shadow defence secretary said: “As Putin seeks to divide the West, we visited Kyiv together to send a clear message that a change in government in the UK would mean no change in our military, diplomatic, financial and political support to Ukraine.

“Moscow’s deepened co-operation with Beijing, Tehran and Pyongyang requires us to deepen our co-operation with Britain’s allies to demonstrate that our commitment to Ukraine will outlast Vladmir Putin’s imperial invasion.

“The next Labour government’s commitment to Ukraine will be ironclad and European security will be our first foreign and defence priority.

“Labour’s action plan lays out a wide-ranging approach to stand with Ukraine, confront Russian aggression and pursue Putin for his war crimes. We will stand with Ukraine until it wins.”

Labour said its plan for Ukraine would include five priorities: fast-tracking military support, deepening diplomatic efforts, targeting Russian aggression, boosting industrial production and supporting recovery and reconstruction.

Earlier on Monday, Mr Sunak used a wide-ranging speech to attack the Opposition’s refusal to adopt the Government’s pledge to spend 2.5% of gross domestic product (GDP) on defence by 2030.

Labour has said it would meet the same target when economic conditions allow.

In a pre-election pitch to voters as the Tories languish more than 20 points behind in opinion polls, the Prime Minister said the ruling party will keep Britain safe as the world endures “one of the most dangerous periods we’ve ever known”.

Sir Keir rejected the accusations, saying the Tories offered “chaos and division” and “we can’t afford another five years” of that.

He told reporters in Wolverhampton: “The first duty of any government, particularly an incoming Labour government, is national security, the security of the country, and that would be my first priority.”