Two French academics jailed in Iran for over half a year on national security charges went on trial Tuesday in a case that has raised tensions between Tehran and Paris, their Paris-based support group said. Fariba Adelkhah and Roland Marchal were detained in June on charges of conspiring against national security that rights groups and fellow academics have denounced as outrageous. Their support group and the French foreign ministry have sounded the alarm over their health -- 60-year-old Adelkhah went on hunger strike for 49 days and 64-year-old Marchals health is said to be deteriorating -- with the coronavirus outbreak only adding to the concern. "A closed-door trial took place this morning in Tehran," the support group said, denouncing a "masquerade of justice". Adelkhah appeared to be present, it said, although Marchal was not in attendance for reasons that are currently unclear. It added that Adelkhah did not appear to have her lawyer present at the hearing and neither were any French diplomats present. The hearing was adjourned to a later date, it said. The support group said holding them in jail was particularly dangerous given the intensity of the coronavirus outbreak in Iran, which has killed 77 people nationwide according to a new toll. "The Iranian authorities are deliberately putting in danger the lives of our two colleagues -- already weakened -- by keeping them in an overcrowded jail while the country is hit by a serious coronavirus epidemic whose scale is being played down and which is not under control," it said. Persian-language media and activists outside of Iran have claimed the scale of the outbreak is far higher than admitted by the authorities but that has been vehemently denied by Tehran. Iran does not recognize Adelkhahs dual French-Iranian nationality and has lashed out at Paris for what it has described as "interference" in the cases. Adelkhah and Marchal, both researchers at Sciences Po University in Paris, are not the only academics being held by Tehran which has been accused by the West of arbitrarily detaining foreigners as bargaining chips. Australian Kylie Moore-Gilbert of the University of Melbourne is serving a 10-year sentence after being found guilty of espionage. Tehran is still holding several other foreigners in high-profile cases, including British-Iranian mother Nazanin Zaghari-Ratcliffe and Iranian-American businessman Siamak Namazi and his father, Mohammad Bagher Namazi.