RIYADH, Saudi Arabia — Saudi Arabia announced Saturday it has broken up planned Islamic State attacks in the kingdom and arrested more than 400 suspects 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 crackdown underscores the OPEC powerhouse’s growing concern about the threat posed by the Islamic State group, which in addition to its operations in Iraq and Syria has claimed responsibility for recent suicide bombings aimed at Shiites in the kingdom’s oil-rich east and in next-door Kuwait.

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 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 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.