LONDON (Reuters) - U.S. President Donald Trump said NATO allies had no choice but to increase their military spending, repeating his demand that all those in the alliance meet the target of spending 2% of GDP a year on defense.

“The prime minister and I agree that our NATO allies must increase their defense spending - we’ve both been working very hard to that end,” Trump told reporters on Tuesday after a meeting with Britain’s Theresa May in London.

He added: “We expect a growing number of nations to meet the minimum 2% of GDP requirement. To address today’s challenges, all members of the alliance must fulfill their obligations. They have no choice.”