He joined foreign ministers and diplomats from Italy, France, Germany, Britain, Poland, Spain, Ukraine and the EU, who themselves vowed to "play an even greater role in ensuring our own security".

Their talks came ahead of a NATO meeting in The Hague on June 24-25, where the focus will be reaching a deal that satisfies US President Donald Trump's demands for allies to spend five percent of GDP on defence.

Rutte is urging NATO members to commit to 3.5 percent on direct military spending by 2032, and an additional 1.5 percent on broader security-related expenditure.

"We are discussing the final decisions we will take in The Hague. I'm pretty confident indeed... that we will get to a joint position, all 32 (members)", he told reporters heading into the talks in Rome.

In a joint statement afterwards, the foreign ministers of France, Germany, Italy, Poland, Spain and Britain, plus EU High Representative Kaja Kallas promised to play their part.

"European countries must play an even greater role in ensuring our own security," they said.

They added: "The NATO summit in The Hague will demonstrate our unity, based on an enduring transatlantic bond, an iron-clad commitment to defend each other, and fair burden-sharing."

They offered again their "unwavering support for Ukraine" -- which was represented by its foreign minister in Rome -- and welcomed Trump's peace efforts, urging Moscow to follow Kyiv's "constructive engagement" in the process.

"We urged Russia to reciprocate without further delay, and to drop its unacceptable maximalist demands and preconditions, to prove it is genuinely interested in peace," they said.

"We deplored recent massive Russian attacks against Ukrainian cities and civilian populations, which are a clear breach of international law."

Italian Foreign Minister Antonio Tajani, the meeting host whose country spends 1.5 percent of GDP on defence, said he was "very happy" with Rutte's spending plan.

"For Italy it's important to spend more but we need more time, 10 years, I think it is more or less possible to achieve this goal," he said.

The meeting of the so-called "Weimar+" group also comes ahead of a G7 summit in Canada on June 15-17, where allies will push Trump to be more aggressive in punishing the Kremlin.

"Euro Atlantic security depends on how we handle the Russian threat. European and US interests remain complementary in this regard," said Polish Foreign Minister Radoslaw Sikorski.

"Stopping Russia remains in the long-term interests of the US. Russia's defeat in Ukraine would be a victory for the US, and in particular for President Trump."