Saudi Arabia is holding 520 suspected al-Qaida-linked militants in custody following several waves of arrests this year, the kingdom's Interior Ministry said Wednesday.
A statement said that 181 others were detained but later released because there was no evidence linking them to the terror movement.
State television reported the 520 suspects were "involved in terrorism."
"These are all new detainees," an Interior Ministry spokesman told Reuters.
Car bomb attacks?
The statement said some of the militants were planning car bomb attacks against an oil installation and a "security" target, but didn't provide further details.
Riyadh has in the past reported arrests of large numbers of militants, including those linked with al-Qaida, but the figure released Wednesday was the largest to date.
Al-Qaida has called for attacks against the Saudi government in the past, criticizing its alliance with the U.S. and hoping to disrupt the flow of oil to the West. The group has also labeled the Saudi government unIslamic, even though the kingdom follows an austere strain of Islam known as Wahhabism.
The ministry said police found money, weapons and ammunition owned by the suspected militants, who had buried some of it in remote areas. The men from regions that included Africa and Asia were organized into various "cells," whose leaders were based outside Saudi Arabia, the statement added.
'Fight security forces'
One of the men was reportedly found with a message from al-Qaida's No. 2 leader, Ayman al-Zawahri, urging him to raise money and saying the terrorist group would provide militants from Iraq, Afghanistan and north Africa "to target oil installations and fight security forces."
Another man who was arrested was trying to raise money in the western Saudi oil hub of Yanbu, where attackers stormed the offices of a Houston-based oil company in 2004.
Some of the suspected militants also tried to recruit Saudis "by spreading misleading propaganda on the Internet" and undermining government-appointed clerics, said the ministry. The statement referred to those detained as members of a "deviant group" — a Saudi euphemism for al-Qaida and its sympathizers.
Saudi Arabia, the birthplace of al-Qaida leader Osama bin Laden, has pursued an aggressive campaign against militants over the past five years, and its security forces have managed to kill or capture most of those on its list of most-wanted al-Qaida loyalists in the country.
In April 2007, Saudi Arabia announced one of its largest anti-terrorism sweeps that netted 172 Islamic extremists. Those arrests stopped plans to mount air attacks on the kingdom's oil refineries, break militants out of jail and send suicide attackers to kill government officials.