The EU's top diplomat Kaja Kallas said Wednesday that the bloc must heed US President Donald Trump's demand to spend more on defence, as she issued a stark warning over the threat from Russia.

Kallas's rallying cry was the latest in a slew of increasingly alarming warnings on defence from European officials, who have been calling for a "wake-up call" on defence since Moscow's tanks rolled into Ukraine in 2022.

Trump has ramped up the pressure by warning Washington's European allies that he could withhold US protection, calling for NATO to more than double its defence spending target.

"President Trump is right to say that we don't spend enough. It's time to invest," Kallas said in a keynote speech at a conference in Brussels. "The United States, they are our strongest ally, and must remain so."

"The EU's message to the US is clear, we must do more for our own........

© International Business Times