The terror suspects included 30 Saudis, 13 Bahrainis, and the rest from seven different nationalities. One of them was a citizen of Brunei.
The Brunei national is the first man from the southeast Asian country to be apprehended on charges of terrorism.
The security sources did not identify the man but said he was arrested in Riyadh without any resistance.
They said the accused is currently being investigated to verify his involvement in terror operations that took place in the Kingdom or if he had any connections with or had supported terrorist organizations in the country.