A total of 31 suspected Islamists in Oman have been sentenced to up to 20 years in prison for plotting a coup.
Six men were jailed for 20 years, while the remainder received sentences ranging from one to 10 years.
They were found guilty of setting up an illegal organisation, raising funds and recruiting members.
The aim of the plot, state prosecutors argued, was to overthrow the government of Sultan Qaboos and to establish an Islamic state.
Handing down the verdict, the judge said the men could not appeal their sentence but could ask for a pardon from Sultan Qaboos.
Correspondents say many of those put on trial are from influential tribes who wanted to restore the imamate - a centuries-old tradition of combined political and religious leadership by an Islamic leader, which was abolished in Oman in 1959.
The 31 accused were among nearly 100 suspected Islamists arrested across Oman earlier this year.
The plot allegedly aimed to oust the sultan in favour of Islamic rule
They were alleged to have been plotting a series of attacks on a popular shopping and cultural festival in the capital, Muscat.
Officials said many of those arrested were released.
Correspondents say the arrests and trials of the defendants have been shrouded in secrecy.
Officials have been slow to acknowledge the action and only a few Omani journalists were permitted inside the courtroom.
Unlike neighbouring Saudi Arabia, Oman has not witnessed any terror attacks and had not been regarded as a potential target of Islamist violence.
In 1994, the Omani authorities announced the arrest of 200 alleged Islamists, who were convicted of belonging to a secret, violent group and given sentences ranging from the death penalty to jail terms. They were later pardoned.