Moroccan investigators questioned around 50 people Wednesday across the kingdom in a major operation targeting suspected militant supporters, local media reported, citing security sources.
Among them, 21 were arrested on suspicion of having pledged allegiance to ISIS group or Al-Qaeda, the reports said, adding anti-terrorist special forces were involved.
Officers seized knives, publications defending "terrorism", and instructions for making explosives, they added, AFP reported.
The North African country has been largely spared acts of violence by militant groups, but its security services often report crackdowns and foiled attack plans.
Last week police in Morocco and Spain said two people, including an ISIS supporter, had been arrested in a joint operation by both countries' security services targeting "terrorists".
