According to the Report, Russian media reported this with reference to a statement from his press service.
Assad claims that he was not going to resign and did not think to ask for asylum during the days of the offensive of the armed opposition. After the militants entered Damascus, he went to the Syrian province of Latakia (where the Russian Khmeimim air base is located) "in coordination with Russian allies and for the purpose of further monitoring combat operations," and flew to Russia in the evening.
In a statement, he claims that he learned about the capture of the capital by militants after leaving Damascus. He considered it pointless to remain president in a country captured by terrorists.