Andriy Shevchenko says football "doesn't exist" for him now amid the ongoing conflict in Ukraine.
Russia invaded neighbouring Ukraine last Thursday after weeks of heightening political tensions between the two countries.
The actions of Russia have led to widespread condemnation, with financial, sporting and political sanctions imposed on the nation in an attempt to deter the attacks.
Shevchenko, who is Ukraine's all-time leading goalscorer and former head coach, has previously asked people to join him in speaking out against the attacks as he called for peace to be restored.
He has stayed in London during the conflict to help lead the humanitarian aid and raise awareness in England, but his family remain in Ukraine in solidarity with their compatriots.
For now, Shevchenko has little interest in the sport that made him famous.
"Football doesn't exist for me any more," he told Sky Sports. "I don't think about it. It's not the time for that. I'm not watching anything, any sport, anything.
"All my concentration, when I wake up, I think about how I can help my country, what I can do. I've started to call my parents, my friends, get updates on what's going on in Ukraine.
"For me, this is my field, this is my concentration now."
However, Shevchenko did note Russia's ban from FIFA and UEFA competitions, praising the decision.
"It's a great reaction from the institutions like UEFA and FIFA to make the right decision," he said.
"I don't think it's a difficult decision. When you attack a country, when you start to send in bombs and soldiers, it's not a conflict, it's a real war.
"When the war has not stopped, I think it's the right decision not to allow any Russian athletes to participate in any sporting event."
