Iranian authorities were seeking an explanation from Budapest for barring the overflight by Foreign Minister Ali Akbar Salehi, after expressing scepticism at the vague official explanation, they said.
Several other EU nations had given permission for Salehi to fly through their airspace so he could attend a five-day conference in The Hague starting on Monday by the UN-recognised Organisation for the Prohibition of Chemical Weapons.
“Although the foreign minister’s plane had already obtained permission to travel through various European airspaces, Hungary withheld its permission, citing technical reasons,” a foreign ministry source was quoted as saying on the web site of state television.
“Since the excuses put forth by the relevant officials were not convincing, we have asked the Hungarian ambassador for an explanation,” the source added.
Iran is subject to several rounds of international sanctions over its disputed nuclear programme.
Salehi, the former head of Iran’s nuclear organisation, was originally on an EU travel-ban list, but was removed after he became foreign minister in January.
The European Union, which already has additional sanctions on Iran, is expected on Thursday to announce further measures targeting 200 Iranian individuals and firms.