US President Donald Trump’s wife, Melania Trump, raised the plight of children in Ukraine and Russia in a personal letter to Russian President Vladimir Putin, White House officials said. Trump hand-delivered the letter to Putin, the officials told Reuters. Slovenian-born Melania Trump was not on the trip to Alaska.

The officials did not divulge the contents other than to say the letter mentioned the abductions of children resulting from the war in Ukraine. The existence of the letter was not previously reported. Russia’s seizure of Ukrainian children has been a deeply sensitive one for Ukraine.

Ukraine has called the abductions of tens of thousands of its children taken to Russia or Russian-occupied territory without the consent of family or guardians a war crime that meets the UN treaty definition of genocide. Previously Moscow has said it has been protecting vulnerable children from a war zone.