US President Donald Trump has announced sweeping tariffs on his country's allies and adversaries, including a 25-percent levy on auto imports starting next week, and a 200-percent tariff on champagne, wine and other alcoholic drinks from the EU.

The duties come amid tensions over defence, with Trump's overtures to Russia over the Ukraine war sparking concern among EU leaders about Washington's commitment to the continent's security.

Meloni, leader of the post-fascist Brothers of Italy party, said Saturday she felt it "my responsibility" to defend transatlantic unity, and "to rebuild it if necessary".

"Of course there are differences on the table on tariffs, but precisely for this reason I also think that we should not act on impulse but in a reasoned way," she told a meeting of the centrist opposition Azione (Action) party.

Just over 10 percent of Italian exports go to the United States, half of them machinery and related components.

Emanuele Orsini, head of Italian business lobby Confindustria, told the same meeting Saturday that a trade war would be a "huge problem for Italy", saying he hoped the EU could negotiate a solution.

Meloni, whose party has a deep eurosceptic streak, told Britain's Financial Times on Friday that the US was Italy's "first ally".

She also sympathised with US vice-president JD Vance's accusation that Europe had abandoned its commitment to free speech and democracy.

"I have to say I agree," she told the daily, adding: "I've been saying this for years... Europe has a bit lost itself."

In response, Elly Schlein, leader of the centre-left Democratic Party, accused Meloni's government of "transforming itself day by day into the Trojan horse of the Trump administration within the EU".

Meloni has however backed plans to boost Europe's defence in the face of Washington's shift, at least in principle, while ruling out sending troops to enforce a possible peace settlement in Ukraine.

One of her two junior coalition partners, Matteo Salvini of the eurosceptic, anti-immigration League party, is strongly opposed to the defence plan, characterising it as a ruse to boost the German economy.