Saudi television has shown what it said were captured terrorists confessing to planning gun and bomb attacks.
Most of the victims of November's attack were non-Saudi Arabs
The men, who were unnamed and whose faces were hidden, said they were lured by promises of paradise and messages from al-Qaeda chief Osama Bin Laden.
The Saudi authorities also said they had seized some 23 tonnes of explosives and hundreds of explosive belts and grenades in the past six months.
Saudi Arabia has vowed to crush all those behind a spate of recent attacks.
In May last year, at least 34 people, including nine suspected suicide bombers, died when a series of co-ordinated truck bombs exploded in foreign workers' compounds across the capital, Riyadh.
In November, 18 people died when suicide bombers targeted mainly Arab foreign workers' compound in the city.
"We thank God we were caught before we carried out any crime," one of the suspects told the television cameras.
Alert said to be based on new information
Another man said he had been won over after being shown fatwas, or religious edicts, on the internet which warned against working for the Saudi Government, which was described as a "false God".
The men also apparently confessed how they had been taken to a house in the capital Riyadh for training in handling weapons. Some said they had been trained in a camp in the holy city of Mecca.
"I was one of them, until recently. Thank God I was jailed and God enlightened me," one of the suspects said.
"We hear the tapes of Osama bin Laden," one of the men said.
A statement by the Saudi Interior Ministry said the recent terrorist acts in the kingdom were carried out by individuals of "misguided and deviant ideology".
The statement, quoted by the state news agency SPA, said those individuals were Saudis who were misled by some extremist criminals.
It said that some of "these people realised they were wrong and surrendered to authorities."
It was not clear if any of the men shown were directly involved in the recent terror attacks in the desert kingdom.
The US has put pressure on Saudi Arabia to act against al-Qaeda since the 11 September attacks on New York and Washington which were carried out mainly by Saudi nationals.
Hundreds of people have been arrested by the Saudi authorities over the past six months.