Russian President Vladimir Putin said Syria needs to start working on a new constitution as a first step to finding a political solution to its civil war, though he acknowledged the process was likely to be difficult.

Putin, who has thrown Russia's support behind Syrian President Bashar Assad with airstrikes, also said in an interview with the German newspaper Bild that the crisis in relations between regional rivals Saudi Arabia and Iran would complicate the search for peace in Syria.

"I believe it's necessary to move toward constitutional reform (in Syria). It's a complicated process, of course. And after that, on the basis of the new constitution, (Syria should) hold early presidential and parliamentary elections," Putin said in the interview conducted Jan. 5.