Saudi Arabia announced Saturday it has broken up planned attacks by the Islamic State of Iraq and al-Sham (ISIS) in the kingdom and arrested more than 400 people suspected of belonging to ISIS cells in an anti-terrorism sweep, a day after a powerful blast in neighboring Iraq killed more than 100 people in one of the country's deadliest single attacks since U.S. troops pulled out in 2011.

The Saudi Interior Ministry accused those arrested over the "past few weeks" of involvement in several attacks, including a suicide bombing in May that killed 22 people in the eastern village of al-Qudeeh. It was the deadliest militant assault in the kingdom in more than a decade. It also blamed them for the November shooting and killing of eight worshippers in the eastern Saudi village of al-Ahsa and for being behind another attack in late May, when a suicide bomber disguised as a woman blew himself up in the parking lot of a Shiite mosque during Friday prayers, killing four.

The ministry did not elaborate on when the men were detained, but previous announcements that scores of suspects have been arrested suggest it was over the course of months. Their alleged offences cited by the ministry ranged from smuggling explosives, surveying potential attack sites, providing transport and material support to bombers, smuggling in explosives from abroad and manufacturing suicide vests.

The Interior Ministry said that in June they thwarted a suicide bomb attack on a large mosque in eastern Saudi Arabia that can hold 3,000 worshippers, along with multiple planned attacks on other mosques and diplomatic and security bodies. It added that the 431 suspects were mostly Saudis but also included Yemenis, Egyptians and Jordanians. Among the suspects so far rounded up were 144 people accused of supporting the network by "spreading the deviant ideology on the Internet and recruiting new members." Some 190 suspects were allegedly involved in plots following bomb attacks on Shiite mosques in Qatif and Dammam, as well as an attack on Saudi security forces. ISIS, which considers Shiites to be heretics, claimed responsibility for the mosque attacks. The group says its priority target is the Arabian Peninsula and, in particular, Saudi Arabia, home of Islam's holiest places, from where it plans to expel Shiite Muslims.

Saudi Arabia branded ISIS a terrorist organization last year and has joined the U.S.-led coalition targeting it in Syria and Iraq. Authorities have vowed to punish those responsible for terrorist attacks inside the kingdom, the Arab world's largest economy. A number of towns were captured by extremists in the province last year, but clashes between the militants and security forces continue. Security forces were out in full force across Diyala on Saturday, with dozens of new checkpoints and security protocols immediately put in place.

Saudi Arabia and its Sunni Gulf neighbors last year joined a U.S.-led military coalition bombing ISIS in Syria, raising concerns about possible retaliation in the kingdom. Interior Minister Crown Prince Mohammed bin Nayef said at the height of the attacks in May that Saudi Arabia's security remained "under control." "Incidents such as this will not destabilize us. We have been through bigger ones," the minister said.