(CNN) -

Saudi Arabia has arrested 88 men who were part of a terrorist network, the Interior Ministry said Tuesday.

They were "on the verge of implementing" plotted attacks inside the country and abroad, the ministry said in a statement.

They came from six terror cells in four regions of the country, including Mecca, said Maj. Gen. Mansour al-Turki, a ministry spokesman.

Some of those arrested are "family members who have sent their sons to terrorist organizations abroad," al-Turki said. Some of the others were trying to travel abroad "to join terrorist groups to conduct terrorist operations."

Most are Saudi citizens, but three are Yemenis, and one person has yet to be identified, al-Turki said.

Fifty-nine of the men had been arrested previously. They were rounded up after months of surveillance.

The arrests are part of a nationwide security operation, the ministry said.