Chastened by the experience of Afghanistan, where hundreds of Saudis fought before returning to sow terror at home, the kingdom is battling to avoid similar blowback from the conflict in Syria, analysts say.
In recent months, Saudi officials have issued increasingly stern warnings against volunteers from the conservative Sunni Muslim kingdom heading off to fight alongside the mainly Sunni rebels trying to oust the Damascus regime.
But diplomats say hundreds of Saudis, perhaps even several thousand, have gone regardless, and judging by death notices and other postings on social networks, their numbers show no sign of abating.
Earlier this month, an Islamist website announced the death of Rashid al-Shelwi, an engineer from the Saudi city of Taif, while fighting alongside the mainstream rebel Free Syrian Army.
On Thursday, the Syrian Observatory for Human Rights reported that a rebel fighter who appeared in a recent video posting executing captured government forces was a Saudi using the nom de guerre Qaswara al-Jazrawi.
Like a significant number of Saudi volunteers, Jazrawi fights in the ranks of the Al-Nusra Front, a US-blacklisted rebel group which has pledged its loyalty to Al-Qaeda, the Britain-based watchdog said.
The involvement of Saudis in jihadist groups has stoked concerns in Riyadh of a resurgence of the deadly Al-Qaeda attacks that rocked the kingdom between 2003 and 2006, and sparked a rare public intervention by King Abdullah.
Without specially referring to the conflict in Syria, the king warned against "those who deceive our children, some of whom have been killed and others imprisoned."
Saudi Arabia's highest religious official, grand mufti Sheikh Abdulaziz Al-Shaikh, chimed in last month with a warning that there was no religious justification for a jihad, or holy war, in Syria.
"The situation in Syria is chaotic due to the proliferation of armed groups that do not fight under a unified banner," the cleric said. "This is not considered jihad... Which must be approved by rulers."
Last June, Saudi Arabia's Council of Senior Ulema, which is headed by Shaikh, already issued a fatwa, or religious edict, prohibiting jihad in Syria without permission from the authorities.
But similar measures failed to stop young Saudis from going to Iraq to fight US-led troops after the overthrow of Saddam Hussein's regime in 2003.
Iraqi officials have said that hundreds of Saudis fought alongside the Sunni insurgents, some of them carrying out suicide attacks against US troops.
Saudi officials have sought to play down the number of volunteers in Syria.
General Saeed al-Bishi, head of Prince Mohammed bin Nayef Centre for Counselling and Care, set up to rehabilitate jailed extremists, said his organisation was helping to dissuade young Saudis from fighting in Syria.
