"The economic damage and the damage to infrastructure exceeds USD 200 billion," Assad told Russian state news agency RIA Novosti.
"Economic issues can be settled immediately, when the situation stabilises in Syria, but rehabilitating the infrastructure will take a long time," he said in comments translated into Russian.
The Syrian strongman said any future contracts to help rebuild the country would be handed out to companies from nations that had backed Damascus during the bloody conflict.
Russia has deployed its military to Syria to back up troops loyal to longstanding ally Assad with a bombing campaign, and the Syrian leader said Moscow's forces would be needed in the country for some time to come.
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"We need their presence as they are effective in the fight against terrorism even if the situation in terms of security in Syria is stabilising," he said, adding that Russia's bases were also required to maintain "balance in the world".
Assad also said that the transitional government of his war-torn country should include both the regime and the opposition. He said that it would be "logical for there to be independent forces, opposition forces and forces loyal to the government represented there".
In the interview, Assad did not touch on his own future, saying only that the makeup of the transitional government should be agreed upon at the negotiations in Switzerland.
The West and Russia say they are pushing for a transitional government to be set up and a draft constitution established by August according to a plan agreed by world powers last year.
He said a preliminary draft version of the constitution could be drawn up "within a few weeks", but insisted that the country would only adopt a new constitution "after the Syrian people vote on it".
Assad rejected the prospect of Syria becoming a federal state -- an option the Kurds have pushed for -- saying the country was too "small" for such a political structure.