The German newspaper writes that an envoy from the US Secretary of Defense informed other member states about the plans last week.
Envoy Alexander Velez-Green reportedly said during the meeting in Brussels that the US intends to reduce the number of fighter jets by a third and halve the number of strategic bombers that NATO can access.
In addition, NATO can expect fewer American warships to assist the alliance, and that no submarines will be made available, the sources said.
The changes are being made by the US within the agreement that regulates which country contributes what, how much and how quickly in the event of a crisis, Reuters reports. The news agency has confirmed parts of Der Spiegel's reporting through its own sources.
The American reduction comes after President Donald Trump's repeated criticism of other NATO countries and his demand that other countries do more.
Last week, Senator Marco Rubio said that Trump is “genuinely disappointed with some allies and their response” to US efforts in the Middle East. Rubio emphasized during the NATO summit in Helsingborg that the US must constantly review where American troops are needed and best serve US interests.
Dutch Prime Minister Mark Rutte last week downplayed concerns about American troop withdrawals from Europe and instead described the situation as an ongoing "rebalancing" that is taking place to avoid relying on a single country, the United States.
