KIEV, Ukraine (AFP) — NATO (North Atlantic Treaty Organization) chief Jens Stoltenberg on Wednesday welcomed a pullback by the Ukrainian army and Moscow-backed separatists in eastern Ukraine, but reiterated calls for Russia to “withdraw all their troops.”

Tuesday saw a long-awaited pullback between the two sides in a key area of the war-torn east.

The move was a precondition for the first face-to-face talks between Russian President Vladimir Putin and his Ukrainian counterpart Volodymyr Zelensky.

“We welcome all efforts to reduce tensions, to withdraw forces and to make sure that we have a peaceful solution to the conflict,” Stoltenberg said in the Ukrainian port city of Odessa, praising Zelensky’s “renewed effort.”

“But we know there is a long way to go because there are still ceasefire violations,” he said as he began a two-day visit to the ex-Soviet country that was set to include a meeting with Zelensky on Thursday.

“NATO states very clearly that Russia has a special responsibility to… withdraw all their troops, all their officers” from eastern Ukraine, Stoltenberg added.

Since coming to power in May, comedian-turned-president Zelensky has sought to revive a peace process to end the five-year-old separatist conflict in eastern Ukraine that has claimed some 13,000 lives.

But those efforts have stalled as Kiev’s forces and the separatists have repeatedly failed to pull back troops from the frontline because of exchanges of gunfire.

Putin said Moscow was “always ready” for talks “as long as they are well prepared and don’t just lead to empty conversations but end with concrete results that are beneficial to a settlement as a whole.”