Iranian authorities have arrested leading activist Reza Khandan, the husband of the prize-winning rights lawyer and campaigner Nasrin Sotoudeh, their daughter and a lawyer said.
"My father has been arrested at home this morning," Mehraveh Khandan wrote on her Instagram page on Friday.
Lawyer Mohammad Moghimi confirmed on X that Khandan had been arrested, saying he believed that the campaigner had been taken in to serve a sentence handed out under a previous conviction.
Later on Friday the Shargh daily newspaper reported that another lawyer representing Khandan, Mahmoud Behzadi Rad, said his client was arrested in relation to a case in 2018.
Rad said Khandan was sentenced to a total of more than four years on two charges.
"Mr Khandan was sentenced to seven months and 16 days in prison for the charge of activity against the system and three years and six months for gathering and collusion (to commit a crime)," the lawyer said.
"We will follow up on the case in the Supreme Court... and try to secure Mr Khandan's release."
Khandan's wife, Sotoudeh, is a lawyer who has spent much of the past decade in and out of prison, serving a myriad of sentences in cases linked to her activism.
She has represented clients in the most sensitive cases, including women jailed for refusing to wear the obligatory headscarf and convicts sentenced to death for crimes committed while minors.
Her husband tirelessly called for her release and promoted her case during her long stints in jail.
Sotoudeh won prizes including the 2012 Sakharov Prize bestowed by the European Parliament and the 2020 Right Livelihood award.
She and the family were also the subject of a well-received 2020 documentary, "Nasrin".
Khandan's arrest cames as a new law is expected to come into force that rights groups have warned will drastically increase the penalties on women deemed to have flouted the Islamic republic's strict dress code.
Amnesty International said in a report on Tuesday that women could even face the death penalty if convicted under the "Promotion of the Culture of Chastity and Hijab" law.