Thirty Russian children whose mothers are in prison in Iraqi for belonging to the Islamic State arrived Sunday in Moscow from Baghdad, Russian authorities said.

The fathers of the children, aged three to ten years old, are believed to have been killed in combat during Iraq's three-year war against the jihadists, a Russian diplomatic source told AFP before their plane departed.

“The plane of the Russian emergency situations ministry has landed," Chechen leader Ramzan Kadyrov said on his Telegram account, adding that it had touched down at Moscow's Zhukovsky airport.

Kadyrov said their arrival was "undeniable proof of the rigorous fulfilment of the mission set out by Russian President Vladimir Putin to save the women and children in Syria and Iraq".

” If we do not bring them home, they

will become the target of the special services of other countries," he added.

The children were taken to hospital on arrival for "thorough examinations", the press service of Russia's health ministry said according to Russia's Interfax news agency.

Kadyrov posted a video clip on the popular Russian network VKontakte of the children's departure from Baghdad, adding that 24 of them were from Dagestan, and another three were from Chechnya.

Several thousand Russians travelled to join the jihadists in their once sprawling "caliphate" straddling Syria and Iraq, according to estimates from the Russian security services.

Some took their families with them.

Since last year, around 100 women and children - mostly from Russia's Muslim-majority Caucasus - have returned under a programme championed by Kadyrov.