NATO's chief said on Monday the alliance does not want a "new Cold War" with Russia, despite members' concerns about Russian military buildup close to NATOs' border.
Secretary-General Jens Stoltenberg spoke at the end of a four-day NATO parliamentary assembly in the Romanian capital. "We are concerned by .... (Russia's) lack of transparency when it comes to military exercises," he said.
He mentioned a Russian-Belarus operation in September involving thousands of troops, tanks and aircraft held in Belarus, on NATO's eastern edge. The drills include manoeuvres designed to hunt down and destroy armed spies.
Still, Stoltenberg said: "Russia is our neighbor.... we don't want to isolate Russia; we don't want a new Cold War."
He said the 29-member alliance had increased jets patrols in the Black Sea in "response to Russia's aggressive actions in Ukraine."
Romanian and Bulgarian pilots have conducted air exercises in the Black Sea in recent months, designed to reassure NATO members uneasy after Russia's interventions in Ukraine.
Speaking about the alliance's mission in Afghanistan, where it retains more than 13,000 troops, Stoltenberg said "the cost of walking away would be much higher" than the human and financial cost of the mission. Afghanistan would descend into chaos and become a safe haven for international terrorists should NATO pull out, he said.
NATO says the Taliban expanded their control of parts of the country after the alliance ended its combat mission in 2014. Some alliance troops have remained to train and advise Afghan forces under the NATO-led Resolute Support mission.
"We have been there for many years, but we have achieved many things...it is no longer a safe haven for international terrorists," Stoltenberg said. "We are in Afghanistan to protect ourselves.