Iran: UN experts alarmed by Tehran's 'violent crackdown' on protests
The experts, who are appointed by the United Nations but do not speak on its behalf, alleged that more than 80 teachers had been arrested or summoned by the authorities in the Islamic republic.
The reported arrests come amid repeated protests by teachers against working conditions and low wages, including one held on May 1 - International Workers' Day - when they took to the streets of several cities, joined by transport workers.
"We are alarmed at the recent escalation of arbitrary arrests of teachers, labour rights defenders and union leaders, lawyers, human rights defenders and other civil society actors," the experts said in a UN statement.
"The space for civil society and independent associations to carry out their legitimate work and activities is becoming impossibly narrow," they added.
The experts also alleged that five people had been killed in wider protests since the start of May, due to "excessive use of force by security forces".
They blamed a government decision to cut food subsidies for fuelling the protests, along with anger over corruption.
The statement called for "those responsible for using excessive force to be held to account through comprehensive and independent investigations".
Iran has been mired in economic crisis since the US reimposed sweeping sanctions after then president Donald Trump in 2018 unilaterally pulled out of a nuclear deal between Tehran and world powers.
The country has in recent weeks also been hit by protests sparked by the May 23 partial collapse of a building in the southwestern city of Abadan.
Authorities say they have arrested 13 officials, including a mayor and two former mayors, in connection with the disaster, one of Iran's deadliest in years.
But supreme leader Ayatollah Ali Khamenei said last month that protests were being exploited by Iran's "enemy", a reference mainly to the United States.
"It's a miscalculation that they think they can make the Iranian nation oppose the Islamic republic," he warned.