Iran has arrested two European citizens and accused them of trying to destabilise the country, the Intelligence Ministry announced on Wednesday.
The ministry did not specify the pair's nationality but said they had entered the country and attempted to get close to the teachers' union with the aim of "unleashing chaos and destabilising society".
For months, teachers in Iran have held protests to demand authorities speed up reforms that would see their salaries better reflect their experience and performance.
The ministry described the pair detained as "two experienced agents" hired by a European country’s intelligence apparatus. It said Iranian authorities had pursued them from “the moment of arrival” and that all their relations with the “illegal Council of Teachers League” were documented.
Sweden said one of its citizens, who was travelling as a tourist, has been detained in Iran, although it was not clear if that case was connected to the Intelligence Ministry’s announcement.
Iran has detained dozens of teachers since the protests began. In April, teachers' union member Rasoul Bodaghi was sentenced to five years in prison over his participation in the rallies, a human rights group said.
Iran's economy has been reeling under punishing sanctions that were reimposed by the United States in 2018, with civil servants among the hardest hit.
The detention comes as EU envoy Enrique Mora visits Iran over its stalled nuclear negotiations with world powers.
The deal, which saw Tehran limit its enrichment for the lifting of economic sanctions, appears deadlocked over an Iranian demand for America to delist the Islamic Revolutionary Guard Corps as a terrorist organisation.
Despite repeated Iranian claims that a separate deal would see billions of dollars in assets unfrozen and prisoners exchanged with the US, the State Department has repeatedly said no deal is imminent on either a prisoner swap or the nuclear deal.
The deal collapsed after then-president Donald Trump unilaterally withdrew from the accord in 2018. Iran has since accelerated its enrichment of uranium — including a small amount to 60 per cent purity, a short, technical step from weapons-grade levels.
Iran’s Foreign Minister Hossein Amirabdollahian offered his support for continuing negotiations.
“Talks for lifting sanctions in reaching good, strong and stable deal is being pursued in its right direction while observing Iran’s red lines,” he wrote on Twitter. However, hard-liners within Iran have criticised any possible bending on the deal or the listing of the IRGC.
Separately, the International Atomic Energy Agency, charged with monitoring Iran’s nuclear programme, has grown increasingly critical of Tehran’s failure to co-operate and its refusal to explain the traces of radioactive material at several undeclared nuclear sites in the country.
Iran has refused to release IAEA surveillance tapes of its nuclear facilities as well, worrying nuclear non-proliferation experts.
Another Iranian citizen faces a life sentence in Sweden.
Iran has long-faced allegations that it uses its arrests as a bargaining chip with the West.
Tehran denies the charges, although negotiations around its landmark 2015 nuclear deal led to Americans being freed in a swap.
Tehran already is threatening to execute Iranian-Swedish researcher Ahmad Reza Jalali, imprisoned since 2016.
Mr Jalali is a Swedish-Iranian physician who specialises in disaster relief and has taught at European universities. Rights groups have condemned his detention.
The announcement of his imminent execution came after Iran summoned its Swedish envoy over a trial in Sweden of an Iranian citizen charged over mass executions committed during the final phase of the Iran-Iraq war in the 1980s.
Swedish prosecutors are seeking life imprisonment for Hamid Nouri, who has been held in custody in Sweden since his arrest in Stockholm in November 2019. The Stockholm District Court said a verdict in the case was expected on July 14.