DOHA (Reuters) - A court in Saudi Arabia sentenced two men to death and 13 others to long prison terms after they were accused of killing a policeman and three civilians and forming an al Qaeda cell in prison, the kingdom's state news agency (SPA) said on Tuesday.
Saudi Arabia has arrested thousands of suspected militants since al Qaeda supporters waged a wave of attacks on residential compounds for foreign workers and on Saudi government facilities starting in 2003, killing dozens.
In 2006 and 2008 security forces foiled planned strikes against oil installations in its Eastern Province.
In addition to the killings, the defendants were charged with setting up an al Qaeda cell in prison and planning attacks against foreign countries, illegal possession of bombs and firearms, forging identities and plans to kidnap non-Muslims.
Three of the 15 men convicted are foreigners. Two Moroccans received jail sentences of 30 and 18 years and a Yemeni a term of 20 years. The others were jailed for between 14 to 35 years, the agency said.
It added that the group had 30 days to appeal.
In recent months, Saudi Arabia imprisoned dozens of people in security trials amid fears that the conflicts in Iraq and Syria will radicalise a new generation of young Saudis.
In February, King Abdullah decreed prison terms of three to 20 years for travelling abroad to fight and of five to 30 years for giving moral or material support to banned groups that the government has designated as extremist.
Saudi Arabia has detained over 11,000 people since the wave of attacks, mostly between 2003 and 2006, against government and foreign targets in the conservative Islamic kingdom staged by al Qaeda militants who had fought in Afghanistan and Iraq.
Officials say there are more than 2,500 Saudis now outside the country who are believed to be operating with militant organisations.
(Reporting by Amena Bakr; Editing by Dominic Evans)