At least 40 teachers and teachers' union activists have been arrested in 10 cities across Iran during and after a round of nationwide protests on Sunday.

Iranian teachers staged demonstrations across the country on May1, the international Labor Day, organized by the Coordination Council of Iranian Teachers’ Trade Associations.

The number of teachers detained during the protest rallies has reportedly been estimated at between 20 and 70, while some have been released so far. A few union activists had been arrested on the eve of Sunday demonstrations.

According to the council, security officers raided the homes of numerous teachers and activists on Monday and used violence during their arrests.

Reports say at least 30 other the teachers have also been summoned and threatened by the Intelligence Ministry in Tehran or its offices in other cities. At least 30 people have been detained by the Intelligence Ministry officers and taken to undisclosed locations.

Teachers say they will continue their protests until authorities meet their demands including the implementation of decade-old legislation that would bring the salaries and pensions of 750,000 teachers in line with other civil servants as well as the freedom of their colleagues who have been imprisoned for their trade union activities.

People from different walks of life, including teachers, nurses, firefighters, and even staff members of the judiciary department and prison guards, have held regular protest rallies or strikes to demand higher salaries.