Deputy Foreign Minister Abbass Araghchi held separate meetings with the three diplomats in Tehran to express Iran's "strong protest" over the detention of Tehran's Vienna-based envoy, Assadollah Assadi, according to the report.
Assadi was detained on Sunday near the German city of Aschaffenburg on a European arrest warrant for suspected involvement in a plot to bomb an Iranian opposition rally in Europe.
His arrest came after a couple with Iranian roots was stopped in Belgium and authorities reported finding powerful explosives in their car.
Araghchi called allegations against Assadi a "plot aimed at damaging EU-Iran relations" ahead of a nuclear meeting on Friday.
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