"We must upgrade massively to protect Denmark. And we must rearm massively to avoid war," Frederiksen told parliament on Tuesday.

She did not disclose any details or sums, but according to Danish public broadcaster DR, the government is expected to announce the creation of a 50-billion-kroner ($7 billion) fund for additional defence spending in 2025-2026.

The government had considered doubling the size of the fund, but determined that there was currently not enough defence equipment on offer to be able to purchase for a larger amount, according to the broadcaster.

Among the items on the government's wishlist are air defence systems, which it does not currently have, DR said.

Frederiksen told parliament the rearming would need to happen "quickly", amidst a "difficult situation for our country, kingdom and continent."

Denmark is currently experiencing "the most dangerous situation in our lifetime."

"This is worse than during the Cold War," she said.

After emergency talks in Paris over the US change in policy on the Ukraine war, Frederiksen warned 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".

Should the Danish fund's size be confirmed at 50 billion kroner, that would bring Denmark's defence spending to three percent of its gross domestic product (GDP), according to Danish daily Berlingske.

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 the outbreak of the war in February 2022, Danish support 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.