(Adds second group of men sentenced to prison)
RIYADH Aug 19 (Reuters) - A Saudi Arabian court has sentenced one man to death and 30 others to prison terms of up to 30 years for their part in a series of militant attacks against government and foreign targets since 2003, state media reported.
The men were part of a group of 50 being tried as a single militant cell and accused of murder and kidnapping, as well as bombing cars, government buildings and foreign residential compounds and plotting to assassinate government officials and attack embassies.
Fourteen of them were sentenced on Monday, including the man facing the death penalty, and 13 others given jail terms of four to 30 years. The other 17 were given prison sentences of two to 25 years in a court session on Tuesday, Saudi Press Agency reported.
Saudi Arabia has detained thousands of its citizens and sentenced hundreds of them to jail after a campaign of bombings and killings from 2003-2006 by an al Qaeda group which killed hundreds.
Riyadh's concerns about domestic militants have grown as the wars in Syria and Iraq have led to what officials describe as a surge in radicalisation among their citizens, and have led some young Saudis to travel overseas to fight.
In February, Saudi Arabia's King Abdullah issued a royal decree imposing prison terms on any Saudi travelling abroad to fight, or who encourages or helps others to do so.
The same decree also demanded jail for those who offer material or moral support to extremist groups, which the government later named as including al Qaeda, Islamic State, Nusra Front, the Muslim Brotherhood, Hezbollah and Yemen's Houthi movement.
Some prisoners have been held waiting trial for years, but it is not clear how long the trials lasted. Saudi Arabia set up a specialised criminal court to handle cases involving militants and security threats.
Rights activists in Saudi Arabia have complained that the government has also used its security crackdown to target peaceful dissidents, something the authorities deny.
Anger at long periods of detention without trial, allegations of torture and other abuses have led to some protests by family members of detainees over the past two years in the capital Riyadh and the city of Bureidah, a traditional centre of support for Saudi royals.
The government denies any abuses and says it does not practice torture. (Reporting by Angus McDowall; Editing by Louise Ireland)