Updated

Several of the more than 100 terror suspects accused of plotting to attack key oil and security facilities in Saudi Arabia were apparently taking their orders from Al Qaeda in Yemen and were ready to strike as soon as they got the go-ahead, a senior Saudi official said Thursday.

In a telephone interview with Fox News, Gen. Mansour Al-Turki, spokesman for the Saudi Ministry of Interior, said the arrest of the alleged plotters not only had prevented the attacks, but broken up a network of Al Qaeda-affiliated radicals that included two suicide bombing cells. He did not dispute news reports indicating that the plotters had been exchanging e-mails with a man in Yemen believed to be a senior leader of Al Qaeda in the Arabian Peninsula, or AQAP.

Al-Turki declined to identify which facilities the suspects were allegedly targeting, but he said one of the suspects, a Saudi national, was employed by a private Saudi industrial security company responsible for protecting oil sites and other critical infrastructure. “As an employee, he had access to all of those sites and to current plans for protecting them,” the general said.

The Ministry of Interior announced on Wednesday that 110 militants had been arrested in round-ups throughout the kingdom in the past five months. On Thursday, the ministry increased the total number of arrests to 113 -- 47 of them are Saudi, 51 Yemeni, and at least one each from Somalia, Bangladesh and Eritrea.

The sweep is among the largest anti-terrorism actions in several years. Saudi officials say that the suspects are members of AQAP, the Yemen-based group that has claimed responsibility not only for terrorist attacks inside Saudi Arabia and Yemen, but also for the foiled plot to blow up an American airliner approaching Detroit last Christmas.

Al-Turki did not dispute press reports indicating that members of the two suicide cells had been exchanging coded e-mails about the planned strikes with a man in Yemen whom the accounts called “Abu Hajer.” One Saudi official said “Abu Hajer,” which in Arabic means “father of Hajer,” is believed to be a nom de guerre for Said Al Shihri, a Saudi leader of AQAP. He was released from the Guantanamo Bay detention center in December 2007 after being held there for six years, and he was taken to a Saudi rehabilitation center from which he disappeared. Al Shihri and another former Gitmo detainee, Ibrahim Suleiman al-Rubaysh, who also fled the rehabilitation center, are now described as senior AQAP leaders.

Al-Turki said the arrests highlight the continuing threat Al Qaeda poses to the kingdom and its crucial oil resources. He described the arrests not only as the result of patient, methodical police work, but also as a near miss.

“They were ready,” he said of the militants, “but waiting for an order which fortunately didn’t come.”

He said that the two bombing teams had put together plans for their attacks, had secured weapons for the strikes and had conducted surveillance of their targets. He said the two cells were composed of six members each – two key players and four militants who were to provide logical support and other backup. One of those under arrest, he said, is a relative of a senior AQAP leader whom he identified as “Al Ahdel.”

The ministry announced that Saudi police had also seized weapons, explosives and ammunition that the militants had hidden underground in basements or in the desert. One press report said that credit cards and cell phones were also found.

Al-Turki confirmed a report in Thursday's Christian Science Monitor that the investigation began last October after two Al Qaeda militants were killed while attempting to infiltrate the kingdom. Rayed Abdullahi Al-Harbi and Yousef Mohammed Al-Shihri, both wearing explosive vests, were gunned down last fall in a shootout with police officers who had tried to check their identities. A Saudi police officer also died in the incident, Al-Turki said. But the police noticed that the militants, both of whom had been on a “most wanted” list that the kingdom issued in February 2009, were carrying two extra explosive vests with them. This led police to conclude that the vests were being smuggled in for operatives already inside the kingdom. Al-Shihri, one of those killed, had also spent time at Guantanamo Bay, the Christian Science Monitor reported.

Al-Turki said the police had spent months quietly tracking down and arresting alleged members of the AQAP cells and had announced the arrests only after they were convinced that they had detained virtually all active members of the network.

Saudi Arabia has arrested suspects in large numbers before, only to let them go after several weeks or months of detention, officials say. In 2007, some 200 alleged militants were detained, many of whom were subsequently released. In 2008, Saudi police detained over 7,800 people in a similar extended sweep, but later released about 200 of them.

Al-Turki said that one of those arrested in the latest sweep is a woman, but that police have not yet determined whether she is an active member of the network or was merely supporting or following her husband or another relative involved in the plot. Most of those arrested are between 18 and 25 years old and were picked up throughout the kingdom, he said. This suggested that the militants’ network was both quite large and widely disbursed, he added.

Arab news reports said that many of the suspects had entered the kingdom on the temporary visas given to enable Muslims to visit holy sites, or by sneaking into the country from Yemen. The kingdom’s porous borders and the hospitality it extends to millions of Muslim believers each year complicate Saudi Arabia's efforts to secure its vast stocks of oil upon which the world’s economy depends.

Toward that end, the U.S. military has been helping the Saudi Ministry of Interior create a special 35,000- member security force dedicated to protecting its oil sites and other critical infrastructure. An American official said that the 3- to 5-year, State Department-led program launched in 2008 to “train the trainers,” the Saudis who will teach the special forces how to patrol and protect their sites, was just getting under way. Saudi Arabia has apparently designated some 14,000 recruits for these special forces, but none has yet been fully trained or is ready for duty, the official said.