Twenty-six foreigners, most of them Syrians, were among those detained in the sweep, which targeted extremists plotting attacks both inside and outside the kingdom, Saudi Arabia’s Interior Ministry said yesterday, according to the official Saudi Press Agency.

Other foreign suspects came from Yemen, Bahrain, Iraq, Egypt, Lebanon, Ethiopia and Afghanistan.

Specific charges included fighting abroad, recruiting young people to fight abroad, belonging to terrorist organizations and financing terrorist groups abroad, Interior Ministry spokesman General Mansour al-Turki said at a televised news conference.

“Daesh and other extremist groups seem to be more successful at infiltrating Saudi Arabia and recruiting Saudi Arabians,” Paul Sullivan, a Middle East specialist at Georgetown University in Washington, said by e-mail yesterday to Bloomberg. “Such arrests have happened in the past, albeit these were seemingly mostly al-Qaeda types. Saudi Arabia has some problems ahead.”

The kingdom ramped up security after ISIS, also known as Daesh and an offshoot of al-Qaeda, seized territory in Syria and neighboring Iraq earlier this year.

Last month, assailants attacked a Shiite ceremony in Saudi Arabia’s oil-rich Eastern Province, killing seven people. Al-Turki said a Saudi suspect in that attack had spent time outside the kingdom. Senior Sunni and Shiite religious scholars quickly condemned the assault, which raised concern that sectarian violence may escalate in the Arab world’s biggest economy.