Russian tanks crossed border into Russia , Russian BBC Minister Avakov says . A skirmish resulted , with Ukrainian forces attacking one column , Avakov says . Russia 's foreign minister tells BBC the claims are false . Ukrainian President talked to Ukrainian leader about peace plan , media office says .
Russian tanks crossed border into Ukraine , Ukrainian Interior Minister Aresn Avakov says . A skirmish resulted , with Ukrainian forces attacking one column , Avakov says . Russia 's foreign minister tells BBC the claims are false . Ukrainian President talked to Russian leader about peace plan , media office says .