A 23-year-old Israeli Arab crossed the border into Syria using a paraglider on Saturday in order to join one of the terror organizations fighting in the country, it was cleared for publication on Sunday morning.
The IDF made no attempts to stop the Jaljulia resident in flight, and he was picked up by someone on the Syrian side after landing.
Both Army Intelligence and the Shin Bet were now working to find the man, said IDF Spokesman Brig.-Gen. Moti Almoz.
The IDF spokesman said the army did not know which organization the young man was trying to join.
A Syrian rebel whose group operates in the area said the paraglider had come down either in Quneitra province or western Deraa. Local rebel groups include the Southern Front alliance affiliated with the Free Syrian Army, the al Qaeda-linked Nusra Front, and a group called the Yarmouk Martyrs Brigade, which other rebels believe is affiliated with Islamic State.
"We don't know if someone was waiting for him on the other side, and we are working under the assumption that anyone who glides against the prevailing wind has planned to do so," Almoz said. "We didn't see where he took off from, but paragliders usually take off from Mevo Hama."
If the IDF and Shin Bet investigation does find that the man intentionally crossed into Syria, Israel will decide how to act, Almoz said, "but on the military front, the incident is almost at an end."
Prime Minister Benjamin Netanyahu told his cabinet on Sunday that he would work to revoke the man's citizenship. "Whoever joins the enemy's ranks to fight Israel will not be an Israeli citizen," Netanyahu said.
After IDF lookouts identified a paraglider making its way from Israeli airspace into Syria, large IDF forces were deployed to the Golan Heights and started searching the border area for the man.
The army has been using drones, aircraft and flares to search for the man from the air, as well as on the ground, and has ruled out the possibility the man was a soldier crossing the border.
Israel is publicly neutral on the Syrian civil war, worried that Assad, a long-time foe with whom it had maintained a stable standoff, could be toppled by more openly hostile Islamists. It has outlawed travel there by Israelis on security grounds, and has cracked down on those suspected of trying to breach the ban.
Arabs, most of them Muslims, make up 20 percent of Israel's population. Inter-ethnic ties have been strained by this month's surge in Palestinian street attacks and Israeli security clampdowns that has killed more than 52 Palestinians and nine Israelis.
Two videos purportedly by Islamic State and circulated on social media last week called for an escalation in the Palestinian violence, which has been fuelled in part by Muslim anger at stepped-up visits by Jews to a contested Jerusalem holy site.
In one of the videos, a masked gunman speaking Hebrew with an Arabic accent threatens Israelis with all-out religious war.
Israel's Shin Bet security service said it could not authenticate the video but one of its official told Reuters that, with more than 40 Israeli Arabs and East Jerusalem Palestinians having left to join Islamic State in Syria or Iraq, the speaker in the video "could be one of them".
Reuters and AP contributed to this report.