More than 30 children have been brought back to Ukraine after being illegally taken to Russia from territories occupied by Moscow, a charity has said.
"Today we are welcoming home 31 more children who have been illegally taken by Russians from occupied territories," Mykola Kuleba, head of the Save Ukraine charity, wrote on social media.
Ukraine estimates nearly 19,500 children have been taken to Russia since Moscow invaded in February last year, in what it condemns as illegal deportations.
The children had been taken from the pro-Western country's northeastern region of Kharkiv and the southern region of Kherson, said Save Ukraine, which fights the alleged illegal deportations of Ukrainian children.
Russia, which controls chunks of Ukraine's east and south, denies abducting children and says they have been transported away for their own safety.
Yesterday, the charity said the children and their relatives had crossed the border into Kyiv-controlled territory.
"Now the fifth rescue mission is nearing its completion. It was special regarding the number of children we managed to return and also because of its complexity," Mr Kuleba said.
The group helped the Ukrainian relatives of children who had been taken to Russia with the logistics, transport and planning needed to embark on the long journey to fetch their children and bring them back.
According to footage released yesterday, the children, who carried suitcases and bags, crossed the border on foot and later boarded a bus to continue their journey.
Mr Kuleba praised the "heroic mothers" who had travelled to retrieve their children in what he called the "most difficult" of the charity's rescue missions to date.
A grandmother who had been due to reunite with two of her grandchildren died suddenly on the trip and the children had to remain in Russia, Mr Kuleba, Ukraine's former commissioner for children's rights, told a media briefing in Kyiv.
Writing on Facebook, he said the Ukrainian relatives had been subjected to a "13-hour interrogation" by Russia's FSB security service.
Mr Kuleba said that all the children who have been brought back to Ukraine by Save Ukraine had said that no one in Russia was trying to find their parents in Ukraine.
"There were kids who changed their locations five times in five months, some children say that they were living with rats and cockroaches," he said.
Three children - two boys and a girl - were present at the media briefing in Kyiv.
Save Ukraine said they were returned to Ukraine on a previous rescue mission last month that returned 18 children in total.
The three children said they had been separated from their parents who were pressured by Russian authorities to send their children to Russian summer camps for what was billed as two weeks, from occupied parts of Kherson and Kharkiv regions.
The children at the briefing said they were forced to remain at the summer camps for four-to-six months and were moved from one place to another during their stay.
"We were treated like animals. We were closed in a separate building," said Vitaly, a child from Kherson region whose age was not clear.
He added that they were told their parents no longer wanted them.
ICC issues arrest warrant for Vladimir Putin
The Hague-based court also issued a warrant against Maria Lvova-Belova, Russia's presidential commissioner for children's rights, on similar charges.
Russia has rejected the allegations of the ICC, saying it does not recognise the jurisdiction of the ICC and calling the warrant against Mr Putin and Ms Lvova-Belova null and void.
Russia has not concealed a programme under which it has brought thousands of Ukrainian children to Russia from occupied areas, but presents this as a humanitarian campaign to protect orphans and children abandoned in the conflict zone.
Kateryna Rashevska, a lawyer from a Ukrainian NGO called Regional Centre for Human Rights, told the briefing they were collecting evidence to build a case that Russian officials deliberately prevented the return of the Ukrainian children back to their country.
"In every story there is a whole range of international violations and it cannot go unpunished," she said.
