WASHINGTON — President Donald Trump arrived in London for the two-day NATO leaders meeting reiterating that too many members of the world's most powerful military alliance still aren't paying enough.

Trump has frequently dressed down NATO counterparts and threatened to reduce U.S. military support if allies do not increase spending. In London, Trump singled out German Chancellor Angela Merkel for not meeting the 2% of GDP spending goal set in 2014.

"So we're paying 4 to 4.3% when Germany's paying 1 to 1.2% at max 1.2% of a much smaller GDP. That's not fair," Trump said Tuesday.

According to the latest NATO figures, the U.S. spends less than Trump noted, at 3.42% of GDP on defense while Germany now spends 1.38%, which is an increase of about 11% from last year.

Germany is only one of 19 NATO members that have not met the 2% GDP spending goal set at the 2014 NATO summit in Wales.

Read more: Three charts that show why Trump thinks NATO is a bad deal

Ahead of the leaders meeting in London, NATO Secretary Jens Stoltenberg announced that defense spending across European allies and Canada increased in real terms by 4.6 % in 2019 — making this the fifth consecutive year of growth.

Stoltenberg also said that by the end of 2020, allies will have invested $130 billion more since 2016.