Maybe they counted everybody who crossed the border from Ukraine to Russia since the troubles started, or something like that.
Yes they say it's the number of people who abandoned Ukraine during 2 last months.
Actually you were probably right about Ukrainian border-guards denying some Russians to cross the border. Rusnovosti.ru said that 342 Russian citizens were denied the right of entry into Ukraine for the last 24 hours. 342 гражданина . I just wonder what a criterion they use to decide whether a certain citizen can be a provocateur or not? I don't think it's a legitimate procedure.