Istanbul, November 29 : President Recep Tayyip Erdogan on Thursday said Turkey could play a mediation role to ease tensions between Russia and Ukraine after the seizure of three Ukrainian ships by Moscow sparked a major new crisis.

Ankara's often brittle relations with Moscow have flourished since mid-2016 in a rapprochement that has sometimes troubled the West. Turkey is working closely with Russia on the Syria conflict and is also purchasing sophisticated Russian air defence systems.

But Erdogan has always sought to emphasise the importance of Turkey's traditionally strong relations with Ukraine, even as Kiev and Moscow remain at loggerheads. Ukraine Accuses Russia of Firing on Its Naval Ships Near Kerch Strait.

"Here we could take on a mediator role and we have discussed this with both sides," Erdogan told reporters at Istanbul airport before heading to the G20 summit in Argentina.

His comments came after intense telephone diplomacy on Wednesday which saw Erdogan hold talks with Russian President Vladimir Putin and Ukrainian counterpart Petro Poroshenko. Erdogan also talked to US President Donald Trump.

"Both Mr Putin and Mr Poroshenko in our talks made requests. We will convey the (Ukrainian) demands to Mr Putin in our meeting in Argentina," added Erdogan, saying the issue would also be discussed in his talks with Trump in Buenos Aires.

Turkey is keen not to see any further escalation in the conflict between its fellow Black Sea littoral states which could bring further instability to the region.

Moscow and Kiev have traded angry accusations since Russian navy vessels fired on, boarded and captured the three Ukrainian ships off the Ukrainian peninsula of Crimea which was annexed by Russia in 2014.

After warning of the threat of "full-scale war", Poroshenko on Wednesday signed an act imposing martial law for 30 days in regions bordering Russia, the Black Sea and the Sea of Azov. Kiev has demanded the return of its ships and the release of 24 sailors taken prisoner during the confrontation.

Tensions between Kiev and Moscow spilt over into confrontation when pro-EU protests in Ukraine led to the ousting of pro-Moscow president Viktor Yanukovych in 2014.

Russia annexed Crimea while pro-Moscow separatists seized parts of the Donetsk and Lugansk regions of eastern Ukraine, declaring unrecognised breakaway statelets in a conflict that remains unresolved.