The event took place at the Qatari Embassy in Moscow.
"We continue to work on reuniting children with their relatives in Russia, Ukraine and third countries ... Three children will soon be reunited with their families in Ukraine, two boys, aged 8 and 15, and a six-year-old girl," Russian Children's Rights Commissioner Maria Lvova-Belova told reporters.
The commissioner also assisted a young man with disabilities in moving to Ukraine.