Differences among European allies over the war in Iran are focusing attention on the network of American military bases located across the continent, as Washington presses partners to allow their use for strikes that President Donald Trump says could last “another month or more”.
Tens of thousands of US troops are stationed across Europe on around 50 bases – a presence that dates back to the period after the Second World War, when Washington chose to keep forces on the continent to prevent another major conflict.
Many of those bases now carry out missions linked to NATO.
But in recent days, Washington has sought to use some of these facilities as part of its war in Iran, triggered by US-Israeli strikes that killed Supreme Leader Ayatollah Ali Khamenei and set off retaliatory Iranian attacks on US bases across the Middle East.
Host countries can refuse, because the bases remain under the full sovereignty of the states where they are located.
What was once a technical detail of military cooperation has suddenly become a political question, exposing divisions across Europe.
Some governments have refused to help, while others have offered political backing – and one leader has changed course after initial resistance.
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UK U-turn
The United Kingdom was initially reluctant to support the US operation. Prime Minister Keir Starmer refused requests to use British military bases for the first strikes on Tehran, saying over the weekend that the UK did not believe in “regime change from the air”.
Trump reacted angrily. Speaking to British tabloid The Sun on Monday, he said it was “sad to see” that the US-UK relationship was “not what it used to be”.
Starmer had not been “helpful”, Trump said – adding that while the United States did not actually need the UK, “he should have helped”.
He contrasted the British position with that of other allies. “France has been great,” Trump said, adding that Germany and NATO had also been supportive. “They’ve all been great. The UK has been much different from the others.”
France and Germany have offered political backing for the strikes and suggested they could play a defensive role in the region.
Starmer later reversed his position and agreed to allow the US to use British bases for attacks on Iranian missile sites.
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Spain holds firm
Spain has taken the clearest stand against the war. Prime Minister Pedro Sánchez said his country would not participate “in any way in the war waged by Donald Trump and Benjamin Netanyahu in Iran”, calling it “a senseless war with unforeseeable consequences”.
He also banned the use of the Spanish bases at Morón and Rota in southern Spain.
The Spanish government said US actions were “unilateral and do not have the backing of multilateral organisations”.
“The bases will provide no support, except in the event of humanitarian necessity,” the country's defence minister said.
The Pentagon has since withdrawn several refuelling aircraft from its bases in Spain.
The dispute has also drawn in the European Union. After Trump reportedly threatened economic retaliation against Spain, EU industry commissioner Stéphane Séjourné said: “Any threat against a member state is by definition a threat against the EU.”
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A longstanding presence
The dispute highlights the scale of the American military presence in Europe.
US troops are stationed across Europe, operating from dozens of installations including major air bases, ports and training areas. In early 2025, the US had nearly 84,000 service members on the continent, according to the US European Command.
The American military footprint in Europe dates back to the aftermath of the Second World War and expanded dramatically during the Cold War, when US troop numbers on the continent peaked at around 475,000 in the late 1950s.
After the collapse of the Soviet Union in 1991, their presence fell sharply to the tens of thousands.
Today the largest concentrations of US forces are in Germany, Italy, the UK and Spain, with smaller or rotational deployments in countries including Poland and Romania. Because the bases sit on host-nation territory, governments retain full legal authority over how they are used.
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As conflict escalates, European leaders have called for restraint.
“The developments in Iran are greatly concerning,” European Council President António Costa and European Commission President Ursula von der Leyen said in a joint statement on 28 February.
They urged all sides to exercise “maximum restraint”, protect civilians and respect international law.
European countries have begun reinforcing their defences in the eastern Mediterranean. France and Greece have moved naval assets towards Cyprus, and France has reinforced air defence systems after drones targeted a British base on the island.
