"If we wanted to surrender, we would have surrendered from the start," Assad told Russian parliament members during a meeting in Damascus, according to Russian news agency Interfax.
"This issue is not under discussion," he said when asked to comment on Western and opposition calls for him to stand down and take part in elections.
"Only the Syrian people can decide who should take part in elections," he said in remarks translated into Russian.
These diametrically opposed positions cast a shadow over the so-called Geneva II conference aimed at setting up a transitional government to lead Syria out of a nearly three-year war estimated to have killed more than 130,000 people and forced millions from their homes.