A Saudi court has jailed five people for up to 30 years on charges including plotting to blow up an oil refinery on behalf of Al-Qaeda, state media reported Monday.
The official SPA news agency gave no details of when the alleged plot against the refinery in the Red Sea port of Yanbu took place.
But the trial is believed to be the latest in a series of prosecutions begun in July 2011 for alleged offences committed during the peak of Al-Qaeda violence in the kingdom between 2003 and 2006.
The court found that some of the defendants had "plotted to blow up the Yanbu oil refinery and participated in preparing car bombs to that end," SPA reported.
"Some have joined Al-Qaeda and are linked to its most dangerous leaderships," it added.
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Other defendants were convicted of lesser arms possession charges and received shorter jail terms, one of just five months.
The court did not pass sentence in Sunday's hearing against two other defendants who were not brought to the hearing, SPA reported, without elaborating if they were tried in absentia.
Al-Qaeda's now slain historic leader Osama bin Laden was Saudi-born and 15 of the 19 perpetrators of the September 11, 2001 attacks in the United States were Saudis.
Saudi authorities launched a massive crackdown on the jihadist network over the past decade that prompted many of its militants to shift base to neighbouring Yemen.
The merged franchise they formed, Al-Qaeda in the Arabian Peninsula, is regarded by Washington as one of the jihadist network's most dangerous.