"The two countries need to increase their defence capabilities, and we see the advantages of closer cooperation. This will not only strengthen the defence of both nations, but will also contribute to overall Nordic and Northern European defence capabilities," Norwegian Prime Minister Jonas Gahr Store said in a statement with the Norwegian government.

The two countries said in a joint statement that there was a "need for Europe to assume a stronger responsibility for European defence" and that both countries were "increasing their defence spending substantially".

Store met his Danish counterpart Mette Frederiksen in Oslo to discuss the closer collaboration, with more concrete details to be announced in May.

"We are already collaborating on maintaining the F-35 aeroplanes. By investing in platforms, weapons systems, joint sensors and ammunition, we can reduce both purchasing and maintenance costs," Store said.

Norway and Denmark are both members of NATO and key providers of Ukrainian military aid.

The Danish government recently announced that it would allocate a further 50 billion krone ($7 billion) in additional defence spending from 2025 to 2026, increasing Danish defence spending to 3 percent of national GDP.

"All European countries are in the same position -- we are ready to spend more money, but it's difficult to buy. It might therefore require us to work more closely together when it comes to capabilities," Frederiksen told Danish news agency Ritzau.

European allies are now talking about further boosting defence investments in the face of Russian aggression and uncertain support from Washington.

British Prime Minister Keir Starmer pledged Tuesday to boost defence spending to 2.5 percent of the economy by 2027, while Germany's next leader, conservative Friedrich Merz, said after his party's election win Sunday that his "absolute priority" would be to strengthen European security.

Doubt has been cast on US President Donald Trump's commitment to European security, as he has demanded that European powers pay more for their own security.