Russia's Daniil Medvedev says he "feels sorry" for Ukrainian players competing on tour amid the ongoing war.
Ukraine's Lesia Tsurenko withdrew from her match against Aryna Sabalenka - who is from Belarus, a Russian ally - at Indian Wells earlier in the week.
Women's world number one Iga Swiatek has also called for more support for competitors from Ukraine, which was invaded by Russia in February 2022.
"I'm for peace all over the world, I've always said the same," Medvedev said.
Russian and Belarusian players have been allowed to compete on both men's and women's tours as individual athletes without national affiliation while the conflict continues.