NATO Secretary General Jens Stoltenberg told the Summit in Washington DC that Ukraine's right to 'self defence' included striking targets inside Russian territory, during a briefing on Wednesday.

"Ukraine has the right for self-defence," he said. "We are helping them to uphold the right of self-defence by delivering weapons, ammunition, missiles. Some of those with long range, including cruise missiles, ATACMS. The right of self-defence includes the right to strike legitimate military targets on the territory of the aggressor, Russia."

Earlier the UK's new PM Sir Keir Starmer also doubled down on his own country's position - first made under the previous administration - saying that it was up to Kiev how to use the country's Storm Shadow long-range missiles.

Moscow accused him of taking an "irresponsible step towards raising tensions" and has previously accused NATO countries taking a similar line to Stoltenberg of escalating the hostilities and coming into 'direct' conflict with Russia.

The NATO chief also said that Ukraine was on an 'irreversible path' to membership but still required 'vital reforms' - while also accusing China of being a 'decisive enabler' in the conflict.

"We also decided to take further steps to bring Ukraine even closer to NATO," he outlined. "As Ukraine continues its vital reforms, we will continue to support them on the irreversible path to NATO membership. The work we are doing together now will ensure that when the time is right, Ukraine can join without delay. It is not a question of if, but when.”

Stoltenberg added that the 'full package' for Ukraine included 'more weapons, including more F-16s' as part of a 'bridge to membership'.

He highlighted the additional - and minimum - '40 billion euros' in military aid pledged by leaders 'within the next year' but also took aim at Beijing for providing 'support' to Russia.

"China has become a decisive enabler of Russia's war against Ukraine and China's support increases the threat Russia poses to Euro-Atlantic security," he alleged.

Western leaders have accused Beijing of supplying 'dual use' items to Moscow's defence industry, although have stopped short of accusing it of sending weapons which China has always strongly denied. The Chinese government has condemned the West for trying to 'interfere' in 'legitimate trade' and said it backs a 'peaceful solution' to the conflict.

Stoltenberg's remarks on 'vital reforms' for Ukraine come after reports ahead of the Summit suggested Kiev would be told it was still 'too corrupt' to join the alliance.

During his speech, the NATO chief also called the alliance 'a bit like a marriage'.

"You have to, in a way, commit every day. But it has proven extremely reliable, this alliance because it is really in the interest of all allies to stand together," he said. "That's the reason why I expect the United States to remain strong. And that's the reason why I expect the United States to remain a staunch NATO ally."

According to reports, there is concern among some allies about the impact of a NATO-sceptic Trump presidency. During the Summit, Hungarian PM Viktor Orban also accused the alliance of being more like a 'war organisation' with 'irresponsible, reckless' support for Kiev. He previously visiting Ukraine, Russia and China as part of his 'peace mission' after taking over the presidency of the Council of the EU - although other EU leaders condemned the move and said he had 'no mandate' from the bloc.