Al-Qaida-linked plotters hoped to reproduce the Sept. 11, 2001, attacks, planning to send suicide pilots to military bases and attack the oil refineries that drive the economy of Osama bin Laden's homeland, the government said.
Revealing new details of the purported plot, a government spokesman said some of the 172 attackers trained as pilots in an unidentified "troubled country" nearby, hoping to use the planes to carry out suicide attacks.
The spokesman, Maj. Gen. Mansour al-Turki, would not say where the training took place: "It could be Iraq, Somalia, Pakistan, there are so many troubled regions in the world. I can't specify."
The militants allegedly wanted to use planes "like car bombs ... to use the aircraft as a tool to carry out suicide operations," al-Turki told The Associated Press by phone from this capital city. Targets included Saudi military bases that militants had no other way of reaching but by blowing up an aircraft, he said.
"The last group (we) rounded up are carriers of al-Qaida ideology, working on achieving al-Qaida goals, which is to take over the society," al-Turki said.
The monthslong roundup of alleged Islamic militants from seven terror cells was one of the biggest terror sweeps since Saudi leaders began an unrelenting offensive against extremists after militants attacked foreigners and others involved in the country's oil industry seeking to topple the monarchy for its alliance with the U.S.
But analysts say al-Qaida followers are determined to stay active in Saudi Arabia, the birthplace of Islam's Prophet Muhammad.
"This is the heart of Islam, the birthplace of Islam. Saudi Arabia has a huge psychological value for al-Qaida. ... Despite the crackdown, al-Qaida will keep trying to establish itself in Saudi Arabia," said Mustafa Alani, director of security and terrorism studies at the Dubai-based Gulf Research Center.
Along with the planned suicide attacks, authorities said the latest arrests also thwarted plots to mount attacks on the kingdom's oil refineries, break militants out of prison and send suicide attackers to kill government officials. The Interior Ministry also said some targets were outside the country, which it did not identify.
Al-Turki did not elaborate or specifically say those detained were al-Qaida members, but his comments marked a rare mention of the terror network by Saudi officials, who customarily refer to the organization as a "deviant group."
Saudi Arabia's long alliance with the United States has angered Saudi extremists, especially bin Laden, who was born in Saudi Arabia. Fifteen of the 19 airline hijackers in the Sept. 11 attacks were also from here.
An austere strain of Islam known as Wahhabism is followed by the country's predominantly Sunni Muslim population, and militant groups have attracted Saudi recruits with extremist leanings.
Militants have attacked foreigners living in Saudi Arabia and the country's oil industry, which has more than 260 billion barrels of proven oil reserves, a quarter of the world's total. Bin Laden also has urged such attacks to hurt the flow of oil to the West.
The four-year U.S.-led war in neighboring Iraq has also provided a training ground for al-Qaida-linked foreign fighters. U.S. officials have warned it could become a regional base for extremists planning attacks elsewhere in the region.
Saudi's ruling family has pursued an aggressive campaign against militants since the May 2003 suicide attack on three housing estates for foreigners in Riyadh. The kingdom's security forces have managed to kill or capture most of those on its list of the 26 most-wanted al-Qaida loyalists in the country.
Sheik Majed al-Marsal, a religious adviser to the Saudi Interior Ministry, told the independent Al-Watan newspaper that he believes Iraq has become the new Afghanistan.
Terror groups "are exploiting the situation in Iraq, recruiting young men, equipping them and training them and then sending them back to work inside their home countries just like what happened in Afghanistan," the cleric was quoted as saying. It was unclear how much al-Marsal knew about the latest arrests.
Faris bin Hizam, a Saudi writer and expert on terror groups, said not only has Iraq been "fertile soil" for young militants, but al-Qaida itself has morphed over the years from a centralized organization to a network of loosely organized terror cells that follow its ideology.
"Al-Qaida which means 'the Base,' has turned from a solid base to a liquid one" that can spread more easily, bin Hizam said. "This is more dangerous simply because you can't put your hand on someone and say this is al-Qaida. You can't hunt down an idea."