Israel has arrested at least seven suspected Jewish militants and placed two more in jail without charge.
The arrests come amid a crackdown on Jewish extremists in the wake of a deadly arson attack in the West Bank, which Palestinians have blamed on Jewish settlers.
An 18-month-old boy died in the attack in July. His father died on Saturday.
The arrests were made in raids on two unauthorised Jewish settlements in the West Bank.
The child’s mother and four-year-old brother remain in critical condition.
Israel put two more alleged Jewish militants in a controversial form of detention without trial on Sunday.
“Meir Ettinger and Eviatar Slonim, who were arrested in recent days, have been placed in administrative detention for six months with the possibility of extension,” the defence ministry said.
Administrative detention – a measure usually affecting Palestinians – allows suspects to be held without charge for six-month intervals and can be renewed indefinitely.
A third alleged Jewish militant had already been placed in administrative detention several days ago.
The three have not been accused of the firebombing, but the move comes as calls mounted for a crackdown on Jewish extremism following the attack in the West Bank village of Duma.
Saad Dawabsha, 32, died in an Israeli hospital where he was being treated for second-degree burns to most of his body. He was buried in Duma on Saturday.
Some of those at the funeral clashed with Israeli border police, hurling stones at them, and they responded with tear gas.
Mr Dawabsha’s son Ali, 18 months, died in the attack in Duma on 31 July, when the family’s small home was firebombed in the night, and daubed with slogans in Hebrew, including the word “revenge”.
Palestinians have accused Jewish settlers of carrying out the attack; Israel has not said whether it holds settlers responsible, and an investigation is ongoing.
Israeli Prime Minister Benjamin Netanyahu called the attack an act of terrorism and has said every effort will be made to catch the culprits.
The incident may have been a so-called “price tag” attack.
Such attacks usually involve acts of vandalism or arson by Jewish militants as retribution for actions taken by the Israeli government against settlements or unauthorised outposts in the West Bank, or for violence by Palestinians.
Palestinians regard settlements as a major obstacle to building a sought-after state in contiguous territory in the West Bank and East Jerusalem, and tensions between the two communities are often high.
About 500,000 Jews live in more than 100 settlements built since Israel’s 1967 occupation of the West Bank and East Jerusalem. The settlements are considered illegal under international law, though Israel disputes this.