RIYADH (AFP) - A Saudi special court sentenced 17 people to between nine and 33 years in jail for joining a "terrorist cell" in the kingdom and fighting abroad, state news agency SPA reported Monday.

The group were found guilty of "adopting an extremist ideology," "disobeying" authorities by travelling to fight abroad and "joining a terrorist cell" inside the kingdom, said SPA.

The group had also "contacted members of the terrorist organisation... established a media outlet in support" of it and "financed terror," said the statement, in an apparent reference to Al-Qaeda.

The men were also accused of "possession of arms and ammunition... to undermine security," in addition to other charges, said SPA.

The 17 are part of a larger group of 67 defendants on trial over similar accusations.

The statement did not specify the nationalities of the defendants or where they had fought.

But in July 2011, the kingdom began a series of prosecutions for alleged offences committed during the peak of Al-Qaeda violence in the kingdom between 2003 and 2006.

King Abdullah in February decreed jail terms of up to 20 years for citizens who travel to fight abroad, as the country struggles to deter young Saudis from becoming jihadists, after Syria's conflict attracted several hundred Saudi nationals.