WASHINGTON — U.S. President Donald Trump on Monday blasted NATO allies on Twitter ahead of his trip to the alliance’s summit this week in Brussels, calling on them yet again to boost their defense spending totals.

“The United States is spending far more on NATO than any other Country. This is not fair, nor is it acceptable,” Trump’s tweet read.

“While these countries have been increasing their contributions since I took office, they must do much more. Germany is at 1%, the U.S. is at 4%, and NATO benefits … Europe far more than it does the U.S.”

The remarks come ahead of Trump’s weeklong trip to Europe, where relations with America’s closest allies are strained over trade and military spending. He meets with Russian President Vladimir Putin in Helsinki after earlier stops in Belgium, England and Scotland.

Trump, who has enraged Canada, Mexico and the European Union by levying tariffs on their steel and aluminum exports to the U.S., also criticized European nations on trade in his Twitter activity Monday:

“By some accounts, the U.S. is paying for 90% of NATO, with many countries nowhere close to their 2% commitment. On top of this the European Union has a Trade Surplus of $151 Million with the U.S., with big Trade Barriers on U.S. goods. NO!”

NATO announced last month that it expects defense spending among its members to rise by 3.8 percent in 2018 and that 15 of its 29 members are on track to meet the NATO guideline of investing 20 percent of defense spending on major equipment this year.