Andriy Yarmolenko was sent off for kicking Ukraine team-mate Taras Stepanenko as a brawl marred a league match between their clubs.
Yarmolenko kicked Stepanenko after the Shakhtar Donetsk player kissed his badge and celebrated in front of Dynamo Kiev fans during his side's 3-0 win.
Both players were sent off - as were two of Stepanenko's team-mates.
"I'd like the whole country to know my friendship with Yarmolenko has ended," Stepanenko, 26, told the club website.
Yarmolenko, also 26, is likely to be given a lengthy ban.
Ukraine have been drawn in Group C with Germany, Poland and Northern Ireland for this summer's European Championship in France, which begins next month.
Coach Mykhaylo Fomenko said: "We have to sort this out so it does not affect our mission."
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