Ankara, Jan 3 : Turkish President Recep Tayyip Erdogan and Russian President Vladimir Putin on Sunday discussed ways to enhance bilateral relations and exchanged views on regional developments, Turkey's presidency said. They discussed "steps to improve Turkey-Russia relations," said the statement, noting that Erdogan reiterated his determination to advance the cooperation between the two countries in all fields, Xinhua news agency reported. The two leaders evaluated regional issues and international developments, especially in the Caucasus, Syria and Libya, it added. Tensions between Ankara and Moscow heightened recently over Turkey's sales of armed drones to Ukraine. Russia is angered over Ukrainian forces using Turkish-made Bayraktar drones in their conflict in the Donbass region. Russia and Turkey jointly operate an observation centre in Nagorno-Karabakh to ensure the ceasefire is maintained between Armenia and Azerbaijan. /IANS