BRUSSELS (AP) — The European Union has gathered evidence that Iran is supplying drones to Russia for use its war in Ukraine and is drawing up a list of sanctions in retaliation, officials and diplomats said Wednesday.

Ukraine’s Western-reinforced air defenses are making it difficult for Russian warplanes to operate, and killer drones are a cheap weapon to seek out and destroy targets while spreading fear among troops and civilians.

Russia is believed to have sent waves of Iranian-made Shahed drones over Ukraine to strike at power plants and other key infrastructure. EU foreign ministers discussed the use of drones Monday, as the 27-nation bloc gathered evidence about Iran’s alleged sale to Russia.

European Commission spokeswoman Nabila Massrali said Wednesday that there is “widely-shared political agreement that the EU should react swiftly now that we have gathered our own sufficient evidence. Work is ongoing in the council (of EU member countries) in view of a clear, swift and firm EU response.”

An EU official and two EU diplomats said that the sanctions could be finalized as soon as Thursday, just as EU leaders are meeting in Brussels. The measures would involve an asset freeze on one “entity” – often a government agency, company or other organization – as well as asset freezes and travel bans several individuals with links to the drone sector. The officials and diplomats spoke on condition of anonymity to provide details about the move before it was agreed.

The foreign ministers also agreed Monday to slap sanctions on Iranian’s morality police as well as 11 officials, including the information minister, over the security crackdown on anti-government protesters.

Follow all AP stories on the impact of the war in Ukraine at https://apnews.com/hub/russia-ukraine.