G7 countries have agreed to stand by Ukraine for “as long as it takes” as they set out the details of what a package of new security measures will entail.

The leaders of the wealthiest economies, which includes the UK, US, Japan, Canada, France, Germany and Italy, jointly penned a security accord at the Nato summit in Vilnius on Wednesday.

Prime Minister Rishi Sunak has said it marks a “new high point” in international support for Ukraine.

He thinks it will send a message to Russian President Vladimir Putin and has the potential to bring an end to the conflict in eastern Europe.

The pact contains promises to act multilaterally and on a country-to-country basis to offer Ukraine long-term security guarantees.

The UK’s side of the bargain will see more Ukrainian pilots trained in Britain.

No 10 said the precise offer for each country will be set out in their bilateral agreements.

In a joint declaration signed by G7 leaders, they said: “We will stand with Ukraine as it defends itself against Russian aggression, for as long as it takes.

“We stand united in our enduring support for Ukraine, rooted in our shared democratic values and interests, above all, respect for the UN Charter and the principles of territorial integrity and sovereignty.”

The group said the mission was to “ensure a sustainable force capable of defending Ukraine now and deterring Russian aggression in the future”.

The pact promises security assistance and modern military equipment, prioritising air defence, artillery and long-range fires, armoured vehicles and other key capabilities, such as air combat.

Ukraine’s military equipment will increasingly be brought into “interoperability with Euro-Atlantic partners”.

Plans are also in place to boost Kyiv’s defence industry, commit to more training exercises and provide support for cyber defence and resilience initiatives.

G7 countries are also pledging to help Ukraine meet the reforms asked of it to become a Nato member.

They added that the West “remains committed to supporting Ukraine by holding Russia accountable” through sanctions and by punishing “war crimes and other atrocities”.