Several houses have been torched in Chechnya after the Russian province's leader called for relatives of Islamist insurgents to be punished in the wake of a bloody attack in the capital Grozny, rights activists said Tuesday.

Sergei Babinets, who works for one of the few human rights groups still active in the restive North Caucasus region, told AFP that four houses were set on fire overnight Saturday by a group of armed men about an hour's drive from Grozny.

The house burnings came after Ramzan Kadyrov, the controversial chief installed by Russian President Vladimir Putin in mostly Muslim Chechnya, threatened collective punishment for families of fighters who stormed into central Grozny December 4, starting a battle in which 24 people died including 14 security officers.

"The time when we used to say that parents do not answer for the actions of their sons and daughters is over," Kadyrov wrote Friday on his Instagram.

"If a fighter in Chechnya kills a policeman or another person, the family of the fighter will be banished immediately without the right to return and their house razed to the foundations."

Chechen leader Ramzan Kadyrov speaks to media in Grozny, on October 5, 2014 Elena Fitkulina, AFP/File

He said that parents and neighbours must bear responsibility for the actions of militants, and punishing them "is in line with norms of Islam."

Rights organisations sharply criticised Kadyrov's statement, and Amnesty International said Tuesday that Russia must investigate the torching of the houses.

"Punishing the relatives of those suspected of involvement in crimes is a flagrant violation of international law. Nothing can justify acts of collective punishment," Europe director for the London-based rights group John Dalhuisen said in a statement.

- 'They poured gasoline inside' -

There was no immediate confirmation that the house burnings in the village of Yandi were related, but the attacks bore the hallmarks of an official raid, said Babinets, who works in the Joint Mobile Group of human rights activists in Chechnya.

"According to neighbours, they came and started setting houses on fire. They threw out the owners, they didn't let anyone take their things and poured gasoline inside," he said, adding that it wasn't clear what happened to the owners then.

A video shot by Babinets (www.youtube.com/watch?v=jxRroHTd93o) shows a brick-walled house gutted with fire and all of the contents reduced to soot and blackened debris, with windows missing and parts of the roof caved in.

A serviceman guards a school building damaged during fighting between militants and police, in Grozny on December 5, 2014 Elena Fitkulina, AFP/File

Babinets said there were rumours of similar incidents in other Chechen towns.

Russia's Committee Against Torture on Tuesday wrote a letter to the Prosecutor-General saying that Kadyrov's calls to punish families of suspected militants contradict Russian law.

Rights organisations say Kadyrov runs the region like his personal fiefdom with disappearances and torture happening regularly and the authorities facing no accountability.

Collective retribution was widespread in Chechnya in 2008-09, with Human Rights Watch recording 25 cases of such house burning in less than one year after similar statements from Kadyrov.

Moscow has battled a simmering insurgency for several years in the North Caucasus after fighting two wars against separatists in Chechnya, and the violence subsequently spread throughout the predominantly Muslim region.