"Twenty-seven Russian children have been repatriated from Baghdad," a Russian foreign ministry official said.

Thirty other children were sent back to Moscow in late December.

The fathers of the children were killed during three years of fighting between the jihadists and Iraqi troops, the official said.

Anna Kuznetsova, Russia's envoy for the rights of children, confirmed the report, according to Russia's TASS state news agency.

She said the 27 children, aged from four to 13 and from 10 different regions in Russia, and were due to arrive home Sunday night.

IS seized large swathes of Iraq in a lightning 2014 offensive, before the government dislodged the jihadists from urban centres and eventually declared victory in December 2017.

The Kremlin announced in early January that 115 Russian children aged below ten -- along with eight aged between 11 and 17 -- were still in Iraq.

Iraqi law allows detainees to be held with their offspring until the age of three, but older children have to live with relatives.

In November, Kheda Saratova -- an adviser to Chechnya's authoritarian leader Ramzan Kadyrov -- estimated "around 2,000" widows and children of Russian IS fighters were still in Iraq and neighbouring Syria.

Around one hundred women and children -- mostly from Caucasus republics -- have returned to Russia so far.

Nearly 4,500 Russian citizens had gone abroad to fight "on the side of terrorists", Russia's FSB domestic intelligence agency said last year.

More than 300 people, including around 100 foreign women, have been sentenced to death in Iraq for belonging to the Islamic State, while others have been sentenced to life in prison.

Most of those convicted are Turks or originate from former republics of the Soviet Union.