Russia has agreed to return four Ukrainian children to their families, as part of a deal brokered by Qatar.

The repatriation is part of a pilot scheme to return more of the thousands of children abducted by Russia following its full-scale invasion last year.

The youngest child of the four is two years old, and the oldest is 17.

Ukraine has said it identified 20,000 of its children taken by Russia.

The International Criminal Court issued an arrest warrant for Russia’s President Vladimir Putin in March, accusing him and his commissioner for children’s rights Maria Lvova-Belova of the unlawful deportation of Ukrainian children.

Russia insisted that its motives were purely humanitarian, claiming it evacuated children to protect them from danger, with top officials scorning the indictment at the time.

The return of the four children will test a scheme worked on by Qatar after it headed talks with Moscow and Kyiv, said a diplomat who asked to remain anonymous due to the sensitivity of the process.

It is hoped that further repatriations would follow if the first was successful, they added.

Qatari minister Lolwah Al Khater confirmed the mediation in a statement, calling the repatriations “only a first step”.

“We are encouraged by the commitment and openness shown by both sides throughout the process, which we sincerely hope will lead to more initiatives aimed at de-escalating tensions and building trust between the two parties,” she added.

However, getting the children out of Russia has not been straightforward. In at least one case a child had to travel home via Estonia, Latvia, Lithuania and Poland.

One of the four children to be returned, a seven-year-old, was reunited with his grandmother on Friday and arrived in Ukraine on Monday.

The other three children, also reunited with their families, are expected to arrive in Ukraine later on Monday or Tuesday.

They are among thousands of Ukraine children forcibly separated from their families, Kyiv says, taken across the border into Russia and faced with an active effort to strip them of their Ukrainian identity.

In some cases Ukrainian families have been forced to make gruelling journeys into Russia to get their children back.