A Washington Post journalist detained in Iran for over eight months is accused of "espionage" and "acting against national security," the semiofficial Fars news agency reported Sunday.

The report did not elaborate on the source of the information, but the agency is regarded as close to Iran's hard-liners.

Iranian officials have said Jason Rezaian is facing "security" charges and that he will stand trial in the Revolutionary Court, which mainly hears cases involving security offenses.

Rezaian, along with his wife, Yeganeh Salehi, and two photojournalists were detained on July 22 in Tehran. All were later released except Rezaian, who is a dual U.S.-Iranian citizen. Iran does not recognize dual nationality.

The Post, U.S. officials and Rezaian's mother have called for his release. They could not immediately be reached for comment.

The Fars report alleged that Rezaian had obtained economic and industrial information from Iran and sold it to unnamed Americans. It also linked him to Omid Memarian, an Iranian opposition journalist based in the U.S.

"Selling Iran's economic and industrial information at a time of sanctions is exactly like selling food to the enemy at a time of war," Fars alleged.

Iran is under crippling sanctions over its nuclear program, which Western nations suspect is aimed at developing an atomic weapons capability. Iran insists the program is for purely peaceful purposes.

Hard-liners in Iran have claimed that Rezaian had access to sensitive information through contacts at the office of President Hassan Rouhani, a relative moderate.