Mansour al-Turki, spokesman for Saudi Arabia's Interior Ministry, said that since December last year officials had arrested 93 people suspected of belonging to the "Islamic State" (IS) group.

At least 77 of these were Saudi nationals wanted for planning terror strikes, including bombing the US embassy in Riyadh.

"Activities are ongoing against the deviant group which seeks to undermine the security of this country… They are ceaselessly seeking to achieve this through their criminal plans," a statement by the Interior Ministry said.

Earlier Tuesday, police arrested a suspected IS operative, Nawaf al-Enezi, ministry spokesman al-Turki told reporters. The 29-year-old militant, accused of killing two police officers, was found in a hideout 100 kilometers (60 miles) east of Riyadh. The Interior Ministry had set a reward of $267,000 for information leading to his arrest.

Saudi officials block terror plans

Security agencies also managed to foil a plot to use a car bomb at the US embassy in Riyadh in March this year, al-Turki said. US officials at the time had decided to halt consular services in Riyadh, Jiddah and Dhahran, but had resumed operations a week later.

Other arrests involved a group of 15 Saudi nationals, called the "Jund Bilad al-Haramain" (Soldiers of the Land of the Two Holy Mosques), who were training in firearms and building explosives, al-Turki told reporters. Another cell of over 60 Saudis tried to recruit members through social media, raise funds and establish training camps within Saudi Arabia's boundaries, the Interior Ministry said.

Saudi Arabia is part of the US-led coalition fighting Islamic State militants in Iraq and Syria. The country has built a complicated double fence system (pictured above) at its border with Iraq to protect itself from IS infiltrators.

The kingdom also launched an air offensive against Shiite Houthi militants in Yemen.

mg/bw (AFP, AP, Reuters)