NATO Secretary-General Jens Stoltenberg has urged Moscow to meet its international commitments to be fully transparent about war games planned for next month in Belarus and western Russia.
"We are going to be watching very closely the course of these exercises," Stoltenberg told journalists in Warsaw on August 25 following talks with Polish Prime Minister Beata Szydlo.
He was referring to the Zapad 2017 joint Belarusian-Russian military exercises that are expected to take place September 14-20.
"All nations have the right to exercise their forces, but nations should also respect their commitments to transparency," Stoltenberg said.
NATO’s secretary-general said that "predictability, transparency, is especially important when we have increased military activity along our borders."
Russia has dismissed concerns over the drills.
Stoltenberg wrapped up his trip to Poland by visiting troops contributing to NATO's enhanced Forward Presence at a military training facility headquarters in Orzysz, 60 kilometers from the border with Kaliningrad, a Russian exclave on the Baltic Sea that borders Poland and Lithuania.
NATO has deployed four multinational battalion-size battlegroups to Poland and the three Baltic states -- Estonia, Latvia, and Lithuania -- to protect and reassure Eastern European member states that are worried about increasingly aggressive moves by Russia following its annexation of Ukraine’s Crimea region in March 2014 and its continued support for separatists in the country’s east.
Stoltenberg told Polish Defense Minister Antoni Macierewicz in Orzysz that the four battlegroups showed "NATO's resolve, NATO's unity" and also sent a "strong message of deterrence," according to the alliance's press office.
"We send a clear signal that an attack on one ally will be regarded as an attack on the whole alliance," he added.
Earlier in Warsaw, Stoltenberg insisted that the troops were deployed to Poland and the Baltic states "to prevent conflict, not to provoke conflict," denying Moscow's repeated accusation that NATO has a Cold War, confrontational mentality toward Russia.
"When tensions run high, dialogue is even more important," he also said. "That's why NATO has always kept channels of communication open with Russia."
At last month's meeting of the NATO-Russia Council -- a forum intended to prevent tensions from escalating -- the alliance and Moscow briefed one another on upcoming military exercises -- NATO's Exercise Trident Javelin 2017 and Russia's Zapad 2017.
Under Organization for Security and Cooperation in Europe (OSCE) rules known as the Vienna Document, states conducting maneuvers involving more than 13,000 troops must notify other nations in advance and be open to observers.
Belarus has said Zapad 2017 involves 12,700 troops -- just under the limit. But NATO members suspect many more troops will end up participating.
Belarus earlier this week said it invited observers from seven countries to the drills.
In an interview with AP on August 24, Stoltenberg said that NATO will send two experts in response to Minsk's offer, adding that this is not enough.
He also said that Russia is using "loopholes" to minimize the number of NATO personnel allowed to observe the exercises.
NATO routinely invites Russia to watch its war games as a confidence-building measure, Stoltenberg told AP, but "Russia has never, since the end of the Cold War, invited any NATO ally to observe any of their exercises."
Speaking to the Rossia-24 news channel on August 24, Russian Deputy Defense Minister Aleksandr Fomin described Zapad 2017 as "a regular, routine joint exercise."
"It is not aggression, as some countries see it," Fomin added. "I do not see any reason to be afraid. Everything, as usual, will be open and friendly."
A NATO official earlier this week told RFE/RL that greater transparency is important to "prevent misperceptions and miscalculations" in response to military exercises.
Russia and Belarus are choosing a "selective approach" to transparency that does not provide observers with opportunities to talk to individual soldiers about the exercises or conduct overflights, this official said.
Lithuanian Defense Minister Raimundas Karoblis warned in June that Moscow might use the maneuvers as cover for an aggressive troop buildup on NATO's eastern flank.
Karoblis said his government estimated that 100,000 Russian troops would be involved in the exercises, rather than the official 12,700.
With reporting by Reuters, AP, Interfax, and Richard Jozwiak in Brussels