TEL AVIV, Israel — A few dozen Israeli citizens have flown abroad in the past two years to join the ranks of the Islamic State, or ISIL, but this weekend marked the first time one of them parasailed over the border directly into Syria.

The event, which was picked up by Israeli sensors, sparked an hours-long search on Saturday by aircraft and troops along Israel's northern border for an innocent glider who may have inadvertently been windswept over the border.

By Sunday, however, the Israeli military announced it had ended the search when it became clear that a young man — an Arab Israeli citizen from the center of the country — had intentionally parasailed across the border to join ISIL or other rebel groups fighting in Syria.

In response to the incident, the Israeli government announced Sunday that it had officially declared ISIL and other Sunni jihadi groups fighting in Syria as terrorist organizations; and that any citizen opting to join them would be stripped of citizenship.

"Those who join the enemy ranks in order to fight against Israel will not be citizens of Israel anymore," Israeli Prime Minister Benjamin Netanyahu said Sunday.

An Oct. 25 statement issued after the weekly cabinet meeting noted that ISIL's hold on territory at Israel's northern and southern borders is expanding as it continues to win "widespread support among Muslims in the Middle East and around the world."

In an Israel Radio interview on Sunday, Israeli Defense Minister Moshe Ya'alon estimated that "a few tens" of Israeli Arab citizens have joined the ranks of ISIL or other groups fighting in Syria.

"Until today, we're talking about an isolated tens of Arab Israeli citizens that have made their way, mostly by way of a flight to Turkey and then on to conflict areas in Syria and Iraq. This was a first by way of hang gliding," Ya'alon said.

"Most of them don't return," he added.

Ya'alon stressed that citizens who have opted to fight for ISIL do not reflect the sentiments of the Arab Israeli community as a whole.. "I don't think the Arab population in the state of Israel supports Da'esh," Ya'alon said, using the Arabic acronym for ISIL.

"But there are young people who are influenced by what they see and read over social networks. They become enthusiastic and take these steps that I'm sure they'll come to regret when they get older."

Ya'alon is scheduled to arrive in Washington on Monday (tomorrow) for talks with his Pentagon counterpart, Defense Secretary Ashton Carter. A statement released prior to Ya'alon's departure Sunday evening defined the visit as "of utmost importance," with the two defense chiefs slated to discuss Israeli security needs and continued US military aid for the coming decade.

"Developments in the Middle East are challenging Israel as well as the United States. In my talks with Defense Secretary Carter, we'll discuss the capabilities that are demanded of the Israel Defense Forces (IDF) in order to deal with events happening around us and their impact on our qualitative military edge," Ya'alon said.