The head of Iran’s human rights council said in an interview with Euronews that he expects Washington Post reporter Jason Rezaian, who was detained by Iranian authorities in July, to be released soon. (Exclusive footage courtesy of Euronews)

Washington Post reporter Jason Rezaian, who has been detained in Iran since July without trial, could be released in less than a month, according to a senior Iranian official.

Mohammed Javad Larijani, who heads Iran’s human rights council and is a top adviser to the country’s supreme leader, said in an interview Monday with the Euronews television channel that security officials have now filed charges against Rezaian alleging “that he was involved in activities beyond journalism.” Larijani said that meant activity “which breaches the security of the state,” but he offered no specifics.

Larijani said in English that the fate of Rezaian, 38, who has dual U.S. and Iranian citizenship, is up to Iranian judicial authorities, but he expressed hope that the case against him could soon be dropped.

[Read the transcript of the interview with Mohammad Javad Larijani.]

“My hope is that before going to the court process, the prosecutor could be content to drop the case to see that maybe the accusations are not quite substantial,” Larijani said, according to a Euro­news transcript of the interview provided to The Washington Post.

Washington Post Tehran correspondent Jason Rezaian was arrested by Iranian authorities on July 22, and he has since been held without charge. (Courtesy of the Rezaian family)

He also said it was possible that the court could pardon Rezaian “and totally drop all the charges,” adding, “Then everything is finished.”

Asked when the case might be resolved, Larijani said, “Well, I anticipate in less than a month.”

Euronews, which is based in France, said the interview would be aired in full Friday. Larijani made similar comments in an interview with the New York Times last week.

Rezaian was arrested July 22 along with his wife, Iranian journalist Yeganeh Salehi, and another couple. Salehi was freed early last month. Rezaian has been prohibited from hiring a lawyer on grounds that no formal charges have yet been filed against him.

Last week, Rezaian’s family called on authorities in Tehran to free him, citing a lack of any evidence against him and expressing concerns for his health. Rezaian, who needs medication to control high blood pressure, is being held in solitary confinement in Tehran’s notorious Evin prison, his family said.

On Thursday, Rezaian’s mother, Mary Rezaian, released a video statement repeating that plea.

“I wake up every morning awaiting a phone call, an e-mail, or even a knock at the door with news that Jason has been released, but there has been no news,” she said in the video.

Jason Rezaian, the Tehran correspondent for The Washington Post, and his wife, Yeganeh Salehi, an Iranian journalist, are shown in Tehran in September 2013. (European Pressphoto Agency)

She added: “I speak directly to those with the power to release my son, Jason Rezaian — enough is enough. You have had 100 days to know my sweet boy, and surely by now you know what his family and friends have always told you: Jason is a good, kind man who loves Iran and its people.”

Citing unidentified sources, the Voice of America reported Wednesday that Rezaian’s physical and mental health have deteriorated since the release of his wife. The U.S. government-owned broadcaster said Rezaian has “several untreated health issues, including a serious eye infection that doctors were concerned could lead to blindness.”

In an interview with CNN’s Anderson Cooper on Thursday, Rezaian’s brother, Ali Rezaian, repeatedly expressed concern for his brother’s health. While saying his brother has not been “physically mistreated,” he noted that he has been kept in solitary confinement throughout his detention.

“I’m really concerned about his health,” Ali Rezaian said. “I’m concerned about his back, about his eyes, about his depression.”

With his brother’s imprisonment stretching beyond 100 days, Ali Rezaian said he was beginning to worry “that it’s getting to a point where there could be long-term damage.”

He said he had been told that Rezaian “did get to see an eye doctor yesterday,” but that his mental health had suffered since his wife’s release.

In the Euronews interview, Larijani, whose brother, Sadegh Larijani, heads Iran’s judicial system, answered vaguely when pressed on the reason for Rezaian’s detention.

“These charges considered by the prosecutor of the case are enough to detain him. . . . So this prosecutor detained him and again renewed his detention because the file was not ready, but I think this dossier is approaching completion,” Larijani said.

He added: “I expect that his case will come to a rather final stage. Either he will be totally discharged or it will go the court, and the court will make a final decision.”