"Iran will adopt the necessary measures in response to this move and and within the framework of reciprocation," Iranian FM spokesman Bahram Qassemi said in a statement published on the ministry's official site.
Initially the statement was made on the Telegram messaging app, where Qassemi wrote that "the Islamic Republic of Iran will take necessary countermeasures in response [ to the EU's step]", noting that Brussels’ decision was surprising, and insisting that the accusations against Tehran were groundless.
Earlier the EU had adopted sanctions, which were linked to Tehran's alleged plots targeting an Iranian opposition event in France and Iranian opposition figures in Denmark.
"The Council added 2 Iranian individuals and the Directorate for Internal Security of the Iranian Ministry for Intelligence and Security to the EU terrorist list (measures set down in common position 2001/931/CFSP). These listings have been adopted by the Council as part of its response to recent foiled attacks on the European soil. These sanctions are effective as of today," the press release read.
The council renewed restrictive measures against those already added to the list, according to the press release.
Commenting on the issue, Stef Blok, the Dutch foreign minister, and Interior Minister Kajsa Ollongren, noted that the reason for the sanctions is that Iran was allegedly involved in the politically-motivated killings.
"[The General Intelligence and Security Service] has strong indications that Iran was involved in the assassinations of two Dutch nationals of Iranian origin, in Almere in 2015 and in The Hague in 2017. These individuals were opponents of the Iranian regime", Blok and Ollongren said in a letter to the president of the country’s House of Representatives.
An agreement between the EU member countries regarding the possibility of introducing anti-Iranian sanctions over the alleged assassination plot was reached in November 2018.The decision was made after the Danish Security and Intelligence Service (PET) in late October accused its Iranian counterparts of plotting an assassination of an Iranian separatist group member in Denmark.
After the EU decision was announced, Iranian Foreign Minister Mohammad Javad Zarif fired back at European officials, saying that no sanctions will "absolve Europe of responsibility for harbouring terrorists".