A week after the reopening of universities in the Iranian new year, authorities have once again begun arresting student activists refusing to wear hijab.

Security forces and plainclothes agents have been deployed at the entrance of the universities to prevent uncovered women from entering, including at Tehran University of Arts, where reports claim “veiled women covered them with shawls”.

The student organizations of the University of Arts called these measures "cheap, insulting and intolerable" adding that large numbers of female students were denied entry for refusing the mandatory hijab. Many girls at universities across the country have received warning texts as the country announced new surveillance measures to catch hijab rebels this week.

Students of Noshirvani University of Babol reported that the messages read: "It has been observed that your clothing in the university environment is not in accordance with the norm announced by the ministry of science and university."

In Al-Zahra University of Tehran, in addition to preventing the entry of students who refuse to observe the mandatory hijab, officials notified all students of the "dress code regulations" on the university portal.

Rules specifically stated that the hijab "must cover their hair and neck" and "short, tight, torn, and unbuttoned clothes and pants are not allowed".

While numbers of arrests are hard to verify in the secretive republic, more than 20,000 Iranians have been arrested since unrest began in September, according to rights group Human Rights Activists News Agency (HRANA).