The European Union Monday widened sanctions against Iran over its support for Russia's war on Ukraine, including targeting vessels and ports used to transfer drones and missiles, as Britain also expanded its measures.
In a move decried by Tehran, the 27-nation bloc said it prohibited the export, transfer, supply or sale from the EU to Iran of components used to make missiles and unmanned aerial vehicles (UAVs).
It also banned any transaction with ports "owned, operated or controlled" by sanctioned individuals and entities - or otherwise used to supply Russia with drones, missiles, related technology and components.
"This measure includes the access to facilities of the ports and locks, such as Amirabad and Anzali, and the provision of any services to vessels," the EU said in a statement as the bloc's foreign ministers met in Brussels.
Amirabad and Anzali are two Iranian ports on the Caspian Sea.
Assistance could still be provided to vessels in need under certain circumstances such as for reasons of maritime safety, the EU added.
The bloc also adopted restrictive measures against Iran's state-run shipping company IRISL, its director Mohammad Reza Khiabani, and three Russian shipping firms accused of ferrying weapons across the Caspian Sea.
Brussels had already imposed sanctions on prominent Iranian officials and entities, including airlines, accused of aiding Russia's war effort.
Acting in parallel, Britain also announced fresh sanctions against Iran Monday, freezing the assets of IRISL as well as national airline Iran Air for transporting ballistic missiles and military supplies to Russia for use in Ukraine.
The British foreign ministry also said the Russian cargo ship Port Olya-3, sanctioned for carrying missiles from Iran to Russia, would not be allowed to enter any UK port.
The British measures build on initial steps announced by the so-called E3 powers of the UK, France and Germany in September over Tehran's alleged supply of short-range missiles to Russia.
Iran rejects Western accusations it has transferred missiles or drones to Moscow for use against Kyiv.
Ahead of the new sanctions' announcement, Iranian Foreign Minister Abbas Araghchi said Sunday the EU was using the "non-existent missile pretext" to target its shipping lines.
"There is no legal, logical or moral basis for such behaviour. If anything, it will only compel what it ostensibly seeks to prevent," Araghchi wrote on X.
"Freedom of navigation is a basic principle of the law of the sea. When selectively applied by some, such shortsightedness usually tends to boomerang."
Iran's economy is already reeling from biting US sanctions following the unilateral withdrawal of Washington in 2018 from a landmark nuclear deal between Iran and world powers.
On Monday, foreign ministry spokesman Esmaeil Baghaei said Tehran would decide how to respond.