The suspect, Ahmed Hiri Shurbaji, 23, was allegedly traveling to Syria in January, along with three other Israeli Arab men, to join the al-Qaeda-affiliated group Islamic State of Iraq and Greater Syria.

In Syria, Shurbaji learned military combat training, participated in battles against the Syrian army, and was indoctrinated in jihadist ideology, according to the Shin Bet.

“In his investigation, Shurbaji admitted he went to Syria to join the struggle against the Syrian army,” the Shin Bet said in a statement.

Shurbaji was arrested April 20 upon attempting to return to Israel. The three other Israeli Arab men have not yet attempted to return.

“The trend of Arab Israelis leaving for Syria entails great danger to the State of Israel,” the Shin Bet said.

According to the Meir Amit Intelligence and Terror Information Center, there are more than 5,000 foreign Arab fighters in Syria.