Saudi Arabia has said it has arrested 88 men suspected of being part of an al-Qaeda cell plotting attacks inside and outside the kingdom.
Tuesday's announcement comes amid the advance of the Islamic State armed group in Iraq and Syria, which has prompted Saudi Arabia to take harsher measures against sympathisers who could threaten the kingdom's stability.
The kingdom made it illegal this year for its citizens to fight with such groups abroad.
Mansour al-Turki, a spokesman for the interior ministry, said 59 of the men arrested had previously served prison sentences for similar offences.
Turki said that security forces monitored the group for months and learned about their plans.
He said the arrests were made over the past several days and that Saudi forces "are serious in tracking down" anyone who joined an armed group.
"It is unfortunate that some of those who had completed their sentences and were released by court orders returned to their previous ways," Turki said.
"They showed their support to the organisations in Syria and Iraq and also in Yemen, and they wanted to get involved in their activities. Some of them tried to get ... instructions of what he should do, how he should act inside the kingdom," Turki said.
The police said that three of the men were Yemeni nationals, one was still being identified and the rest were Saudi nationals.
Yemeni authorities have said that Saudis were increasingly crossing the border into Yemen to deliver funds or receive rebel training.
Saudi security officials began battling al-Qaeda fighters around a decade ago when members launched a string of attacks in the kingdom aimed at toppling the monarchy.
Over the weekend, Saudi King Abdullah warned that rebel fighters could attack Europe and the US if there is not a strong international response to terrorism. His remarks were believed to be in reference to the Islamic State group's offensive.