Iran denounced Sunday what it labelled "baseless accusations" made by Slovenia's Premier Janez Jansa at a meeting of an opposition group reviled by Tehran, and summoned its ambassador.
The foreign ministry charged that Jansa's participation at a meeting Saturday of the exiled People's Mujahedin (MEK) was "unacceptable and undiplomatic".
It said it had summoned Slovenia's ambassador to Tehran, Kristina Radej, to express its "strong protest" to the country that has since July 1 held the European Union's rotating six-month presidency.
The MEK's political wing, the National Council of Resistance of Iran (NCRI), on Saturday held a meeting at its base in Albania that included by video conference lawmakers, officials or former ministers from the United States, Britain and France.
Jansa told the meeting in an online message that the "Iranian people deserve democracy, freedom and human rights, and should be firmly supported by the international community".
He also demanded that the "Iranian regime must be held accountable for human rights violations".
The Slovenian prime minister said he backed calls for justice for "the families of the 30,000 political prisoners who perished" during what she termed the "horrible 1988 massacre".
He urged the United Nations to "shed light" on the mass executions of detainees at the end of the 1980-88 Iran-Iraq war, when MEK fighters launched an offensive against the Islamic Republic from Iraqi soil.
"This is especially important in light of the fact that the regime's next president will be Ebrahim Raisi, who is accused by Amnesty International of crimes against humanity for his role in the massacre," he said.
Raisi, the head of the Iranian judiciary, won June elections and takes office in August.
Asked in 2018 and again last year about the executions, Raisi, who was Tehran's deputy prosecutor general at the time of the events, denied playing a role.
But he lauded an order he said was handed down by the Islamic republic's founder Ayatollah Ruhollah Khomeini to proceed with the purge.
According to the MEK, 30,000 detainees, mostly affiliated with the Islamic-Marxist movement, died.
British academic Michael Axworthy, in his book "Revolutionary Iran", estimates that "the reality is probably nearer 4,000 to 5,000" people killed.