Donald Trump has threatened to withdraw more US troops from Germany after stunning European leaders and some senior members of his own party by last week announcing the withdrawal of 5,000 soldiers from Germany.

The move left 30,000 US troops still in the country, according to CNN. But Trump threatened on Saturday that more cuts were coming. “We are going to cut way down, and we’re cutting a lot further than 5,000,” he told reporters on Saturday.

Trump’s initial move to reduce US personnel in Germany came after German chancellor Friedrich Merz said the US was being “humiliated” by Iran.

The Pentagon then announced on Friday it was withdrawing 5,000 troops from Germany. The decision came after a “thorough review of the Department’s force posture in Europe and is in recognition of theater requirements and conditions on the ground”, a spokesman said.

Speaking to students last month in Marsberg, Merz said “the Iranians are obviously very skilled at negotiating, or rather, very skillful at not negotiating, letting the Americans travel to Islamabad and then leave again without any result.”

“An entire nation is being humiliated by the Iranian leadership, especially by these so-called Revolutionary Guards. And so I hope that this ends as quickly as possible.”

The Republicans who chair the armed services committees in Congress, Senator Roger Wicker of Mississippi and Representative Mike Rogers of Alabama, released a joint statement on Saturday saying they were “very concerned” by the possibility of reducing troops in Germany.

“Germany has stepped up in response to President Trump’s call for greater burden sharing, significantly increasing defense spending and providing seamless access, basing, and overflight for US forces in support of Operation Epic Fury,” they said in a statement, using the military name for the campaign against Iran. Any reduction in troops should be done in coordination with Congress and allies.

“Rather than withdrawing forces from the continent altogether, it is in the US interest to maintain a strong deterrent in Europe by moving these 5,000 US forces to the east,” they added. “Those allies there have made substantial investments to host US troops, reducing costs for the US taxpayer while strengthening Nato’s front line to help deter a far more costly conflict from ever beginning.”

Merz’s comments highlighted tensions between the US and Nato as well as European allies over the war in Iran and other foreign conflicts. A Pentagon email leaked to Reuters floated punishing Spain, which has been a loud critic of the war, and suspending it from the Nato alliance.