Unidentified assailants attacked a Roma schoolgirl, whose deportation from France sparked controversy, along with her family in Kosovo where they have been living since their eviction, police said.
A police officer, who requested to remain anonymous, told AFP that the Dibrani s were walking in Mitrovica with their children when they were attacked by unknown people.
The mother of 15-year-old Leonarda, Xhemaili, was "beaten and is in hospital while the children, who are traumatised, are at a police station", the officer said.
Meanwhile, another police officer said that four people were detained over the incident which, according to first findings, may have been caused by some previous private affairs.
"The incident occurred between two families, the Dibranis and the Bislimis," police captain Ahmet Gjosha said.
"It turned out that Mr Bislimi was Xhemaili Dibrani's husband 25 years ago and we assume that this fact sparked the incident."
The Beslimi family was repatriated from Switzerland four months ago, he said.
Police said they were taking the incident very seriously and a probe was launched.
Shortly after the incident a police officer had told AFP that "it shows that the Dibranis are not safe here".
Leonarda's father Resat Dibrani, 47, was at the hospital by his wife's side.
On Saturday, French President Francois Hollande offered Leonarda the chance to go back to France, but without her family.
Hollande's offer was immediately rejected by the girl while her father said that the family, deported on October 9, would not be divided and would return to France by any means.
Her parents and five brothers and sisters had lived in France for four years while their asylum bid was processed.
It was eventually rejected in the summer.
Leonarda Dibrani's eviction caused an outcry in France because she was detained during a school trip before being deported with her family, and students took to the streets demanding she return and Interior Minister Manuel Valls resign.
In an interview with AFP Thursday, Resat Dibrani said he was born in Kosovo and that his wife and five of his six children, including Leonarda, were born in Italy.
He said he had lied about his family's Kosovo origins to have a better chance of obtaining asylum.
Earlier on Sunday, the father told AFP that his "children are afraid to go out".