Premier Mette Frederiksen told a press conference that the money was being sent to the military with the message: "Buy, buy, buy."

"Buy what can contribute to a stronger defence and thus to a stronger deterrence here and now," Frederiksen said, stressing the need to act quickly.

"If we can't get the best equipment, buy the next best thing, and if the wait time for what we want most is too long, choose something else that can be delivered faster," Frederiksen said.

"There's only one thing that counts now, and that's speed," she said, adding that Denmark had a particular need to invest in air defence systems.

Frederiksen had already said earlier this week that the plans would be announced, citing a need to "rearm massively to avoid war."

Speaking to reporters Wednesday, Frederiksen pointed to an increased threat from Russia.

"We are facing an aggressive Russia that is rearming," she said, while citing the "harsh reality" that "Russia produces more ammunition in three months than NATO does in a whole year."

After emergency talks in Paris over the US change in policy on the Ukraine war on Monday, Frederiksen said that Russia is "threatening all of Europe now".

The war in Ukraine has been about Russia's "imperial dreams, about building a stronger and a bigger Russia, and I don't think they're going to stop in Ukraine", she told reporters.

She warned the US against attempts to agree on a "fast" ceasefire that would give Russia the chance "to mobilise again, attack Ukraine or another country in Europe".

The additional funds will bring Denmark's defence spending to three percent of its gross domestic product (GDP), which Frederiksen noted was "the highest level in more than half a century."

US President Donald Trump has demanded that NATO allies more than double their defence spending targets to five percent of GDP.

The United States currently spends around 3.4 percent of GDP on defence.

Denmark has been one of Ukraine's strongest backers.

Since Russian invaded in February 2022, Danish aid to Ukraine has amounted to some $7.52 billion in military support and around $741 million in civilian contributions, according to the Danish foreign ministry.