"While the war continues to take lives, it is of critical importance that the ceasefire be implemented as soon as possible," he said at the opening of the talks at Istanbul's Dolmabahce Palace.

The talks must also work towards bringing Ukraine's President Volodymyr Zelensky and Russian President Vladimir Putin together, Fidan said as he officially opened the talks.

"It is also very important that these talks form the basis of a leaders' meeting. We wholeheartedly believe it is possible to reach peace through constructive negotiations," he added.