Germany, France and Britain on Tuesday condemned what they said was Iran's delivery of ballistic missiles to Russia for use in the Ukraine war and declared new sanctions targeting air transport.
"We will be taking immediate steps to cancel bilateral air services agreements with Iran," the three European countries said in a joint statement, adding that they would also "work towards imposing sanctions on Iran Air".
US Secretary of State Antony Blinken earlier had said, on a visit to London, that Russia had received shipments of the ballistic missiles and "will likely use them within weeks in Ukraine".
London, Paris and Berlin said that, despite their warnings of "new and significant measures against Iran" in case it sent missiles, "we now have confirmation that Iran has made these transfers".
"This is a further escalation of Iran's military support to Russia's war of aggression against Ukraine and will see Iranian missiles reaching European soil, increasing the suffering of the Ukrainian people," they said.
"This act is an escalation by both Iran and Russia, and is a direct threat to European security."
The three countries said they "will be taking immediate steps to cancel bilateral air services agreements with Iran".
"In addition, we will pursue the designations of significant entities and individuals involved with Iran's ballistic missile programme and the transfer of ballistic missiles and other weapons to Russia.
"We will also work towards imposing sanctions on Iran Air," they said, echoing a step taken by Washington.
Shortly before the joint announcement, Iran's foreign ministry spokesman Nasser Kanani denied that the Islamic republic had made weapons transfers, in a message on the social media platform X.
He wrote that "spreading false and misleading news about the transfer of Iranian weapons to some countries" was "ugly propaganda" and a lie.
He charged that its aim was to conceal "the dimensions of the massive illegal arms support of the United States and some Western countries for the genocide in the Gaza Strip", where Israel is at war with Palestinian militant group Hamas.