Netanyahu said he is seeking to have Arab Israelis stripped of their citizenship for joining ISIS.

Israeli Prime Minister Benjamin Netanyahu said Sunday he is seeking to have Arab Israelis stripped of their citizenship for joining the Islamic State of Iraq and Syria (ISIS) group to fight in the Syrian conflict.

Last week, Israeli police said six Arab Israelis were arrested on suspicion of planning to travel to Syria to join ISIS in a case sparked by a man’s paraglider journey.

On October 24, a 23-year-old entered Syria illegally on a paraglider from the Israeli-occupied Golan Heights, prompting an investigation by Israeli security forces.

Israeli authorities say about 45 Israeli Arabs have joined the ranks of ISIS in recent months, with some having been killed.

Ten who returned to Israel were arrested.

“I have asked the attorney general to advance steps to revoke the citizenship of those who join ISIS,” Netanyahu said on Sunday.

“Whoever joins ISIS will not be an Israeli citizen. And if he leaves the borders of the state, he will not return,” he said at the start of a cabinet meeting.

“I think this lesson is becoming increasingly clear throughout the international arena and it is fitting that we lead this effort as well.”

Concern over foreign fighters travelling to and from Syria to fight with ISIS has risen in the wake of the November 13 Paris attacks.

Arab Israelis are those who remained in the Jewish state after its 1948 creation and account for more than 17 percent of the country’s population.