The men were indicted on charges of supporting a terrorist organization, possessing and distributing advertising materials of an illegal group, and conspiracy, among other accusations, according to a written statement from police spokeswoman Luba Samri.
Among the six suspects: four schoolteachers, one of whom taught at an elementary school in Hura. According to police, the man took "every opportunity" to teach his young students about ISIS.
Police say the teacher would sing songs praising ISIS in class, express his support for the terrorist organization, and show students map drawings of the self-proclaimed Islamic State -- the group's preferred moniker, and also the way it refers to its wide swath of territory across Syria and Iraq.
He even posted support videos to YouTube, but later removed them. Police say he'd been "warned that it might interfere with his work as a teacher."
"We should act in the strongest possible way against teachers who take advantage of their jobs in such an unspeakable way," Israel's Minister of Education Naftali Bennett said. "Instead of guarding the students, they harm them."
"We will maintain a clean education system," Bennett said. "We will not allow anyone to contaminate our children."
What we know about the suspects
The men were conspiring to travel to Syria to join ISIS, according to police.
All six are residents of Hura, a Bedouin village near Israel's border with the West Bank. Israeli police say four of them taught in schools, ranging from elementary to high school, located in Hura and Rahat, another Israeli city inhabited mostly by Bedouins, an Arab Muslim minority in Israel.
The suspects identified as educators are teacher Hamza Abu Ali Abu Alkyan, elementary school teacher Akram Al'ab Ahmed Abu Alkyan, high school teacher Muhammad Al'ab Ahmad Abu Alkyan and elementary school teacher Bashir Jabran Salim Abu Alkyan.
Police did not specify what the other suspects, Khader Hassan Abu Alkyan and Sharif Shahada Abu Alkyan, did for a living.
Based on the birth years released by police, the men range in age from their early 20s to early 30s.
Investigating a 'secret squad of supporters'
The Southern Negev counterterror unit and the Israeli Security Agency, also known as Shin Bet, opened an undercover investigation into the men when they were suspected "of starting a secret squad of supporters for Da'esh." Da'esh is another name for ISIS, which is also known as ISIL.
The investigation took place under a gag order during May and June of this year, according to police.
Negev District Commander Brig. Gen. Amnon Alkalay said the gag order was lifted once the indictments were filed.
Not the first Israeli ISIS arrests
While there haven't been many ISIS-related arrests on Israeli soil, the number is growing.
In January, Israeli intelligence announced that seven Israeli-Arab men had been accused of trying to set up a local ISIS cell. They planned to perpetrate attacks against Druze Israelis and security forces, according to the Israel Security Agency. The group included a lawyer from Nazareth, who reportedly referred to himself as a commander of ISIS in Palestine.
And in February, Israeli intelligence arrested an Israeli-Arab man from Nazareth and charged him with fighting for ISIS. He was arrested at Ben Gurion International Airport upon his return to Israel. He had been seriously wounded in a coalition airstrike during a battle near Falluja, Iraq, according to the Israel Security Agency.
According to testimony from the director of the U.S. National Counterterrorism Center in February, more than 20,000 fighters from more than 90 countries have traveled to the ISIS battlefield.
Increased tension on Israel-Sinai border
The announcement of the arrests comes on the heels of a rocket attack against Israel from Sinai.
The rockets landed in southern Israel on Friday, the first such attack since the summer of 2014. They hit the Eshkol Regional Council but failed to cause any injuries or damage, police said.
ISIS affiliate Sinai Province, previously known as Ansar Beit al-Maqdis, has claimed responsibility for the rocket attack, according to Reuters. Israeli Prime Minister Benjamin Netanyahu condemned the attack.
Tensions have been mounting along the Israeli-Egyptian border, where ISIS claimed responsibility for coordinated attacks last week that killed 17 Egyptian soldiers and injured 30 others.
The Sinai Province group pledged allegiance to ISIS last November. The group has been designated as a terrorist group by the United States since April 2014.
In the last month, rockets from Gaza have landed in southern Israel three times, according to the Israel Defense Forces. That tally includes a rocket on June 23 that landed near Yad Mordechai, a community just north of Gaza. An additional rocket fired at Israel fell short and landed in Gaza.
The Omar Brigades, a Salafist group in Gaza claiming loyalty to ISIS, has taken responsibility for some of the rocket attacks, which did no damage and caused no injuries. In response to the attacks, the IDF struck "terrorist infrastructure" in Gaza. The retaliatory airstrikes caused no injuries.