Finnish PM Sanna Marin has said Europe is "not strong enough" to stand up to Russia's invasion of Ukraine on its own, and has had to rely on US support, Ednews reportc citing BBC.

During a visit to Australia, the leader of the pending Nato member said Europe's defences must be strengthened.

"I must be brutally honest with you, Europe isn't strong enough right now," she said. "We would be in trouble without the United States."

The US is by far the largest provider of military assistance to Ukraine.

Since the start of the war in February, it has committed $18.6bn (€17.7bn; £15.2bn) in support, a research briefing last month by the UK's House of Commons said.

The second largest donor is the European Union, followed by the UK, the Kiel Institute for the World Economy says. But their contributions are dwarfed by those of the US.

And with European countries' military stocks depleting as they supply Ukraine, Ms Marin said more needed to be done to bolster European defences.

Speaking at the Lowy Institute think tank in Sydney on Friday, Ms Marin said: "The United States has given a lot of weapons, a lot of financial aid, a lot of humanitarian aid to Ukraine and Europe isn't strong enough yet."

She added that Europe must make sure it is "building those capabilities when it comes to European defence, European defence industry, and making sure that we could cope in different kinds of situations".

While in office, US President Donald Trump regularly criticised European countries in Nato for not spending enough on defence.