"That's a lot of money," Scholz told news site Focus online, adding that "we have a very clear procedure in NATO" on decision-making, with alliance members currently asked to spend two percent of GDP on defence.

The centre-left leader said that for Europe's biggest economy, five percent of GDP would mean around 200 billion euros ($206 billion) per year, and that Germany's federal budget is around 490 billion euros.

Meeting Trump's demand would therefore force Germany to save or borrow an additional 150 billion euros a year, Scholz said.

"And that's why I think it's better to concentrate on the path that NATO has long agreed on," he said.

He conceded, however, that "Germany must do more for security" and stressed that Berlin had already roughly doubled annual defence spending to almost 80 billion euros over recent years.

After Russia's full-scale invasion of Ukraine in 2022, Scholz also announced additional defence spending of 100 billion euros to upgrade Germany's armed forces.