The decision fulfills Trump’s announced desire to withdraw troops from Germany, at least in part due to its failure to spend enough on defense. U.S. officials said that some moves will begin in months and would likely send air and ground forces to countries that already have an American troop presence. The plan leaves about 25,000 troops in Germany.

The announcement is closely tied to the plan to increase the U.S. troop presence in Poland, a shift long-desired by Warsaw and Polish President Andrzej Duda. The officials, who spoke on the condition of anonymity to discuss plans not yet announced, said the moves will cost “billions” and require construction at bases in the U.S. to accommodate the additional forces. The officials said that in the future other troops would rotate in and out of Europe.

Members of Trump’s own political party have criticized the troop move as a gift to Russia and a threat to U.S. national security. Twenty-two Republicans on the House Armed Services Committee fired back with a letter to Trump saying a reduced U.S. commitment to Europe’s defense would encourage Russian aggression and opportunism.