Four more activists with Lehava, a group that opposes Arab-Israeli coexistence and assimilation, were arrested.
Four other members of the controversial organization also were brought in for questioning on Sunday.
The arrests came less than a week after the head of Lehava, Benji Gopstein, was arrested in his West Bank hometown of Kiryat Arba. Nine other Lehava members also were arrested in raids across the country on suspicion of incitement to violence early last week.
Three Lehava members were charged Dec. 15 with vandalizing and setting fire to an Arab-Jewish school in Jerusalem, the Max Rayne Hand in Hand School, last month. The charged members reportedly admitted to the arson attack.
The Lehava activists arrested or detained on Sunday are from Jerusalem, Rishon Lezion, Beitar Illit, Netivot and Herzliya.
Lehava opposes intermarriage and joint Jewish-Arab initiatives. Members of the group staged a protest this year opposite a marriage between an Israeli Muslim man and a Jewish woman.