A prominent Algerian journalist has been remanded into custody under a state security law, according to the news outlets he directs.

“Journalist Ihsane El Kadi, who was arrested Friday night … has been placed in pretrial detention” by an investigating judge in Algiers, the news website Maghreb Emergent said on Thursday.

It said he was being detained under a law relating to receiving “funds, donations or advantages … for carrying out or inciting acts” that threaten state security or “national unity”.

El Kadi, a vocal critic of the government, is accused of receiving foreign funding, his lawyers said after he was arrested on December 24. He could face up to seven years in prison.

Radio M, which he also runs, said El Kadi had appeared before the investigating judge “without his lawyers, who were not notified”.

The day after his detention, police sealed off the headquarters of Interface Media, which runs both the outlets, and seized documents, it reported.

El Kadi was sentenced in June to six months in prison after a former information minister lodged a complaint against him over a Radio M article. The official complained that it was about Rachad, a Muslim organisation Algeria says is a “terrorist” group.

The minister also accused El Kadi of “divulging information likely to be detrimental to the national unity”.

The sentence was confirmed on appeal, but the court did not order El Kadi’s detention. He might not have to serve the prison time because sentences are often suspended in political cases.

The authorities’ moves against El Kadi and his outlets have generated an outpouring of support among journalists and human rights defenders in Algeria and beyond. About 800 people have signed a petition for his release.

Reporters Without Borders, the international media freedom group, condemned El Kadi’s arrest and called on authorities to “free him and respect the work of the media in the country”.