RABAT: The trial in Morocco of two leading Islamist figures in their 60s over an alleged "sex on the beach" incident opened Thursday with the couple submitting medical certificates for their absence.

Court sources said a brief hearing was held in Benslimane, south of the capital near the seaside town of Mohammedia, where the allegedly unmarried couple, Omar Benhammad and Fatima Nejjar, were arrested on Aug. 20.

The trial opened in the absence of both accused, who submitted medical certificates, the sources said, and was adjourned until Sept. 22.

Nejjar, a 62-year-old widow, faces adultery charges, which on conviction can carry a prison term of between one month and a year, while Benhammad, 63, is accused of "attempted corruption" of the policemen who arrested them.

Benhammad's legitimate wife has not pressed for adultery charges, and he has argued in his defense that he and Nejjar have a common law marriage.

The couple are both vice presidents of the religious wing of the Justice and Development Party (PJD), which has led a coalition governing the conservative Muslim kingdom since late 2011.

They have been suspended from the Unity and Reform Movement following Moroccan media reports of their arrest in a "sexual position" in a car on the beach.

Nejjar, who has publicly called on young women in Morocco not to give in to "temptation and vice," has been ribbed on social media over the arrest.