BERLIN (Reuters) - The German government has reassured the North Atlantic Treaty Organization (NATO) it will stick to its plans to continue increasing military spending to reach 1.5 percent of gross domestic product by 2024 despite declining tax revenues, Der Spiegel magazine reported on Tuesday.

Two German Eurofighter jets simulate the interception of a plane over the Baltic sea November 1, 2018. The German air force has five Eurofighter jets based in Estonian Amari as part of NATO's air policing mission for the three Baltic states. REUTERS/Sabine Siebold

Those plans had been called into question on Monday after a Finance Ministry document obtained by Reuters showed the government’s tax revenues were likely to rise less than expected in coming years due to a slowing economy.

The document showed the ministry had earmarked just 7.3 billion euros ($8.34 billion) for further defense and development aid spending through 2022, a sum seen as insufficient to allow Germany to reach the 1.5 percent target, which is already below a larger NATO target of 2 percent of GDP.

Germany is under pressure from the United States and other NATO members to boost military spending to 2 percent of GDP, in line with a target agreed in 2014 by members of NATO.

Der Spiegel said Germany’s envoy to NATO delivered a three-page document to NATO Secretary General Jens Stoltenberg on Tuesday with a binding pledge to boost spending to 1.5 percent of GDP by 2024 and continue increasing it thereafter.

The document did not, however, include any figures or a timetable for how Berlin will achieve the higher spending outlays, Spiegel said. It noted the German budget would have to expand to over 60 billion euros from 43.2 billion euros now to reach the targeted percentage.

Military spending remains a source of great tension within Germany’s ruling coalition, with Chancellor Angela Merkel’s conservatives pushing for quicker increases in defense budgets while the Social Democratic coalition partners are riding the brakes.

The issue is also a major irritant in ties between Germany and the United States.

Asked about the ministry document, Richard Grenell, U.S. Ambassador to Germany, on Monday urged Germany to stick to its NATO commitments.

“NATO members are expected to reach their 2 percent commitment by 2024. Now is not the time to take NATO for granted or undercut it in any way,” he said.