Sweden would contribute 2.1 billion kronor and Denmark the remainder to supply Ukraine with the TRIDON Mk2 mobile anti-aircraft artillery system, the two countries' defence ministers told a press conference.

Danish Defence Minister Troels Lund Poulsen said the donation would "strengthen Ukraine's air defence capacity".

"Which, unfortunately, has been under severe pressure in recent months," he said, alongside his Swedish counterpart, Pal Jonson.

"This is a platform that can take out cruise missiles and can take out long-range strike drones and it's a capability that the Ukrainians need due to the increase of the Russian long-range strike capabilities," Jonson told AFP in Gothenburg.

Jonson stressed that it was a new system developed at "record pace".

"It's been adapted to the lessons learned from the battlefield," Jonson said.

The donation would be enough for Ukraine to create its own air defence battalion "if they so wished", Jonson told reporters.

An AFP analysis on Monday found that Russia fired fewer drones and missiles in January compared to the month before but still crippled Ukraine's energy infrastructure.

The most serious electricity, heating and water outages of the nearly four-year war have pushed the country towards a humanitarian crisis.