BRUSSELS -- NATO Secretary-General Jens Stoltenberg has characterized the latest session of the NATO-Russia Council as a "frank and useful discussion" of Ukraine, Afghanistan, and risk reduction.
Stoltenberg made the comments at a press conference following the July 13 meeting, saying that NATO and Russia "continue to have fundamental disagreements," particularly regarding Russia's 2014 annexation of the Ukrainian region of Crimea and its role in the war in eastern Ukraine.
NATO and Russia also briefed one another on upcoming military exercises -- Russia's Zapad-2017 and NATO's Exercise Trident Javelin 2017. Stoltenberg said Russia had in particular provided numbers of its soldiers, planes, and ships involved in the Zapad war games in Russia and Belarus in September -- an exercise that has deeply worried the allies.
Stoltenberg said such voluntary exchanges were encouraging, but "do not substitute for the mandatory transparency required under the Vienna Document."
"It was significant that at today's meeting, we exchanged advance briefings on upcoming exercises," Stoltenberg said. "I am encouraged by this progress."
But he warned that "from previous experience, we have every reason to believe it may be substantially more troops participating than the officially reported numbers."
Rules for military exercises in Europe known as the Vienna Document set thresholds for the number of troops allowed to take part in exercises before the opposing side is allowed to demand a mandatory inspection.
Exercises involving 13,000 or more troops are subject to mandatory inspections. In the case of exercises involving 9,000 or more soldiers, the other side must be notified.
"We call on Russia to adhere to the Vienna Document," which is negotiated under the Organization for Security and Cooperation in Europe, Stoltenberg said.
Stoltenberg said the Russian side gave figures but declined to make them public, saying it was up to Moscow to do so.
He said Trident Javelin was in contrast only a "command post" exercise, involving 5,000 personnel in preparation for next year's much larger Trident Juncture maneuvers with around 30,000 troops.
NATO allies such as the Baltic states and Poland are deeply suspicious of Russia.
They say Russia has carried out exercises involving many more troops -- reports cite figures of up to 100,000 -- but formally splitting them up in such a way as to get around the rules.
The talks were expected to focus on measures to reduce tensions and risks after recent incidents involving maneuvering by warplanes flying over the Baltic Sea.
Russia has denied military involvement in the conflict in Ukraine despite substantial evidence it has provided troops, mercenaries, and military equipment via the part of Ukraine's border that is controlled by the separatists.
Before the NATO-Russia Council meeting, NATO officials told journalists they will press for Russian pilots to file flight plans, respond to air traffic control, or identify themselves with cockpit transmitters when flying in the Baltic area.
NATO said last month it tracked three Russian aircraft over the sea, including two jets which it said did not respond to air traffic control or requests to identify themselves.
Moscow maintains that all Russian flights over the Baltic comply with international law.
For its part, Russia said it scrambled a jet last month to intercept a nuclear-capable U.S. B-52 bomber it said was flying over the Baltic, in an incident that had echoes of the Cold War.
The NATO-Russia Council is a forum intended to prevent such tensions from escalating.