Russia's President Vladimir Putin and US counterpart Barack Obama held frank talks on Syria amid US concern over Turkish shelling of Kurdish militia targets in northern Syria days before a ceasefire deal is due to take hold, AFP reports.

Putin took the call from Obama and both sides "gave a positive evaluation" of the results of talks in Munich last week, according to a Kremlin statement, which called the exchange "frank and business-like".

The Russian leader reiterated that a united anti-terrorist coalition was needed in Syria, where Moscow has led an aerial campaign to support the regime's ground operation since September.