Italy refused US authorisation to use the Sigonella air base, Italian news agency ANSA reported on Tuesday, citing local media and informed sources.
The refusal came after a US flight plan showed a stopover at Sigonella en route to the Middle East.
Italian Defence Minister Guido Crosetto denied permission, ANSA said, noting that no formal authorisation had been requested and the Italian military command had not been consulted.
The flight plan was communicated while the aircraft were already in the air, and checks confirmed these were not regular or logistical flights covered under Italy’s existing treaty with the United States.
The move comes a day after Spanish government officials confirmed that Spain has denied the United States the use of its airspace for flights linked to the war involving Iran.
The restrictions also apply to US aircraft stationed in third countries such as the United Kingdom and France, Spanish military sources told El Pais.
Washington had also explored deploying strategic bombers such as B-52 and B-1 aircraft to bases in southern Spain, but the proposal was dropped after Madrid made clear it would not support operations without international legal backing, El Pais added.
Tensions in the Middle East have escalated since Israel and the United States launched a joint offensive against Iran on February 28, resulting in more than 1,340 deaths, including then-Supreme Leader Ali Khamenei.
Iran has retaliated with drone and missile strikes targeting Israel, Jordan, Iraq and Gulf countries hosting US military assets, causing casualties and infrastructure damage, while disrupting global markets and aviation.
