South Africa has become a key source for ISIS of not only money, but also jihadist fighters who typically hail from a small area of Johannesburg, diplomatic and intelligence officials told Fox News.

Young South Africans are flocking to the Middle East to join the black-clad terrorist army in Syria and Iraq, typically flying to Turkey and then making their way south to the so-called caliphate, according to officials.

“We could say with certainty that 50 to 60 persons, South African citizens, have joined ISIS in Syria, [but] there are some reports suggesting that more than a hundred have done so, and as many as 300 or more,” Iraqi Ambassador to South Africa Hashim Al- Alawi told Fox News.

“We could say with certainty that 50 to 60 persons, South African citizens, have joined ISIS in Syria, [but] there are some reports suggesting that more than a hundred have done so, and as many as 300 or more.”

- Hashim Al- Alawi, Iraqi Ambassador to South Africa

Al-Alawi believes there could be many more ISIS recruits leaving South Africa who get to the front line undetected. While ISIS recruits come from throughout the country, most are radicalized and lured from two downtown districts of Johannesburg, Mayfair and Fordsburg. Two South Africans killed ealier this year in Syria came from the area, which also was once home to Samantha Lewthwaite, the British so-called “White Widow” terrorist.

Non-Muslims are not welcome in the downtown area known for spawning terrorists. A Fox News crew that recently tried to film near a Mayfair mosque was threatened and chased from the area. The ominous encounter raised for the first time the specter of “no-go zones,” or areas where Muslim extremists have sole control of the streets.

Sources told Fox News ISIS, working through the Internet and through radical clerics on the ground, is using sophisticated psychological methods to brainwash and recruit young South Africans. The radicalizing messages include instructions on how to get from Africa to Syria and Iraq without detection.

Those who respond to ISIS’ call leave through Johannesburg’s main international airport, where just weeks ago, five men were nabbed with $6 million and believed headed for the Islamic State. Earlier this year, a 15-year-old girl was pulled from a plane minutes before takeoff after her family told police she had taken a large amount of money and disappeared. She was on a flight to Turkey, to slip into Syria to become an ISIS bride of war.

Institute for Security Studies analyst Martin Ewi said it is no mystery why some South Africans want to join ISIS.

"It is because of their belief in the message, the propaganda," Ewi said.

Sources told Fox News South African authorities are concerned enough about the situation to have established a specialized a deep undercover unit dedicated to stemming the outgoing tide of jihadist warriors, a development intelligence officials would neither confirm nor deny.

Paul Tilsley is a freelance reporter/ producer for Fox News, operating out of Johannesburg, South Africa. Follow his African stories @paultilsley