Former world number one Andy Murray said Tuesday he would donate his prize money from tennis tournaments for the rest of the year to UNICEF's Ukraine appeal.

The British player said he was working with the United Nations children's agency to help victims of the conflict following Russia's invasion of its neighbor late last month.

UNHCR, the UN Refugee Agency, recorded more than two million refugees on its dedicated website on Tuesday and UNICEF believes hundreds of thousands of them are youngsters.

"Over 7.5m children are at risk with the escalating conflict in Ukraine, so I'm working with @UNICEF_uk to help provide urgent medical supplies and early childhood development kits," Murray tweeted.

"It's vital education continues, so UNICEF is working to enable access to learning for displaced children, as well as supporting the rehabilitation of damaged schools, together with replacement equipment and furniture.

"I'm going to be donating my earnings from my prize money for the rest of the year, but anyone in the UK can support UNICEF's humanitarian response by donating to our appeal."

Murray recently appointed eight-times Grand Slam singles champion Ivan Lendl as his coach for a third time, reuniting with the man who guided him to all three of his major titles before he suffered serious hip problems.

The 34-year-old Scot, currently ranked 88th in the world, has been able to train and play consistently but his recent results have been disappointing apart from a run to the final of the ATP Tour event in Sydney in January.