Duma West Bank arson attack
Mourners next to the body of 18-month-old Ali Dawabsheh, who was killed after his family's house was set on fireReuters

Israel has jailed a right-wing Jewish activist amidst an unprecedented crackdown on extremist Jews in the wake of the murder of Palestinian toddler Ali Saad Dawabsha in the West Bank and the fatal stabbing of a teenager at a gay pride rally last week.

It marks one of the first times that Israel has used the law – which allows terrorism suspects to be jailed indefinitely without charge or trial and is typically used against Palestinians – against a militant Jew and comes a day after another prominent right-wing figure, Meir Ettinger, was arrested.

A statement from the Israel Defence Ministry said that Mordechai Meyer, 18, was jailed over "his involvement in violent activities and recent terror attacks".

No specifics were given, but Israeli media reported that Meyer had been linked to an attack on a Galilee church last year that came amidst a spate of attacks on Christian churches ahead of the visit of Pope Francis to Israel and Palestine.

Ettinger, the 23-year-old grandson of infamous American rabbi Meir Kahane, was arrested on Tuesday 4 August accused of participation in extremist Jewish organisations and is still being held by Israel's Shin Bet security agency.

A third man, Eviatar Slonim, was arrested "for belonging to an extremist organisation", a Shin Bet spokeswoman told AFP on Tuesday. No details were provided on any charges against him

There has been no indication that any of the men were involved in the murder and arson attack in Duma on Friday, which killed 18-month old Dawabsha and serious injured his mother, father and brother. The attack was believed to have been carried out by Jewish extremists in retaliation for the demolition of an illegal settlement near Bet El early last week.

The murder drew renewed attention to the extremist tactic of "price tagging" in Israel, a euphemism for hate crimes committed by pro-settlement activists that are said to be extracting a price from Palestinians for perceived Israeli government failures to support settlements, which are illegal under international law.

Last year, amidst a spate of attacks, prominent Israeli author Amos Oz referred to Jewish extremists as "neo-Nazis" and last week Israeli prime minister Benjamin Netanyahu promised a zero-tolerance approach to right wing zealots in Israel and the West Bank.

Ettinger has an unrivalled pedigree of far right anti-Arab zealotry in Israel. His grandfather advocated expelling Arabs from Israel and swathes of the Middle East including large parts of Jordan, Syria and Iraq right up to the River Tigris, which he claimed was the biblical homeland of the Jewish people.

Kahane, who founded the US-based Jewish Defence League (JDL) which exists to this day and the now-outlawed Kach political party, was assassinated by an Egyptian-American gunman in New York in 1990. He was in favour of complete segregation between Jews and non-Jews.

Israeli media reported this week that Ettinger had formed a cell that planned to carry out a series of attacks against Palestinians that would trigger the end of days. It quoted a rambling document seized by Israeli police and penned by the 23-year-old that outlines his plan to spark riots and anarchy.

"Israel has many 'weak points', subjects people [to] tiptoe around so as not to cause riots. What we will do is simply 'spark' all these powder kegs, all the questions and the contradictions between Judaism and democracy. Between the Jewish character and the secular character, without fearing the results," it said.

Ettinger, whose mother was Kahane's daughter, Tova, has long been a pro-settlement activist in the West Bank, Israeli media reported. He began in a fringe settlement outpost in the West Bank, where a group of young settlers occupied Arab land and was later jailed for his actions against Israeli soldiers.

He later gravitated towards the infamous Israeli settlement of Yitzhar, where right-wing activists are frequently involved in anti-Arab attacks. The leader of the group, Rabbi Yitzhak Ginsburg, has previously claimed that Arab have no right to be in the West Bank.

Israeli Army Radio reported Meyer's lawyer, Adi Keidar, as saying that he opposed administrative detention for both Israelis and Palestinians and that the security services could have taken "less drastic steps" towards his client, who has in the past been banned from the West Bank and Jerusalem.