Two former militant supporters confessed on Saudi state television on Tuesday night how they organised the Internet operations of Al Qaeda's campaign against the Saudi government, media said.

"Al Qaeda in the Arabian Peninsula" began a campaign to destabilise the US-allied Saudi government in 2003 with two suicide bomb attacks on foreign housing compounds in Riyadh.

The violence was brought to an end by Saudi security forces in cooperation with foreign experts in a counter-insurgency campaign that won plaudits in the West.

The last major attack was a failed attempt to storm the world's largest oil processing plant at Abqaiq in February 2006.

Abu Azzam Al-Ansari and Umm Osama -- both Egyptian -- explained on Saudi television how they set up the online magazines Sada Al-Jihad and Al-Khansaa promoting jihadist thought and carrying news of the militant campaign.

Ansari was arrested last year, Asharq Al-Awsat newspaper said on Wednesday, but Sada Al-Jihad has continued publishing. It was not clear when Umm Osama was arrested.

Saudi authorities have detained hundreds of suspects over the past year, many of who are accused of promoting "takfiri" ideology that deems some Muslims as infidels based on what they see as violations of the sharia, or Islamic law.

The Interior Ministry said last week it was holding 520 suspects, arrested since January, who planned to stage car bomb attacks against oil and security installations and who had used the Internet to win support and gather money.

Internet monitoring has become a key part of the government's campaign against militant groups and the TV confessions appeared to be part of an ongoing efforts to keep Saudis away from militant ideology. Hundreds of sites are blocked by state censors. - Reuters