MOSCOW (REUTERS) - The presidents of Russia and Turkey on Wednesday (Sept 29) held talks on curbing renewed violence in north-west Syria and on possibly expanding Moscow's sales of military defence systems to Ankara despite US objections.

The talks took place in the Russian Black Sea resort of Sochi and the Kremlin said that President Vladimir Putin was ending a period of coronavirus-related self-isolation by meeting Turkish President Tayyip Erdogan.

Neither leader made any detailed statements to the media after the talks, though Mr Putin thanked Mr Erdogan for the visit, which he called useful and substantive.

Turkish officials said before the meeting that Mr Erdogan would press Mr Putin for a return to a ceasefire agreed last year to end a Russian and Syrian army assault on Turkey-backed fighters in Syria's Idlib region.

"The steps we take together regarding Syria carry great importance. The peace there is dependent on Turkey-Russia ties," Mr Erdogan told Mr Putin at the start of their talks.

Mr Putin made only a passing reference to Syria in his opening comments, saying it was one of the areas where the two countries cooperated fairly successfully.

The Russian leader said negotiations with Turkey were sometimes difficult but that the two countries had learnt how to find mutually beneficial compromises.

A potential Turkish purchase of more Russian S-400 missile defence batteries was on the agenda too, something that Washington has made clear it strongly objects to.

In an apparent reference to the Americans, Mr Erdogan told Mr Putin he wanted to discuss further defence cooperation regardless of US objections.

"At the UNGA (UN General Assembly), the typical persons especially asked us about certain issues specifically of course," Mr Erdogan told Mr Putin.

"We gave them the necessary response anyway. It is not possible for us to turn back from the steps we took. I especially believe this: it is of great importance for us to continue by strengthening Turkey-Russia ties every day."

Nato member Turkey bought Russian S-400 missile defence batteries in 2019, triggering US sanctions against its defence industries and warnings from Washington of further action if it bought more Russian equipment.

Mr Erdogan last week indicated Turkey still intended to procure a second batch of S-400s, saying no country could dictate Ankara's actions.