BRUSSELS — NATO's secretary-general on Tuesday rejected Moscow's claim that its military incursion into alliance airspace over Turkey wasn't intentional or important, saying there were two separate incidents and "the violation lasted for a long time."
Jens Stoltenberg, the NATO chief, told a news conference in Brussels the reported incidents were "very serious."
Stoltenberg added, "It doesn't look like an accident, and we've seen two of them over the weekend."
In a statement, NATO spokesperson Carmen Romero said Stoltenberg later confirmed that NATO generals, using pre-existing and dedicated military-to-military lines of communication with Moscow, would be contacting their Russian counterparts about the alleged entry of Russian warplanes into Turkish skies.
"It's unacceptable to violate the airspace of another country," Stoltenberg told reporters. He said NATO is expressly worried that such acts by the Russians could have unforeseen consequences.
"Incidents, accidents, may create dangerous situations," Stoltenberg said. "And therefore it is also important to make sure that this doesn't happen again."
On Monday, NATO ambassadors met in special session and condemned what they termed Russia's "irresponsible behavior."
The ambassadors also called on Russia to cease such practices.
A Turkish government official confirmed Tuesday that Russian Ambassador Andrey Karlov was called to the ministry on Monday afternoon during which Turkish officials lodged a "strong protest" over the second infringement.
The official spoke on condition of anonymity in line with Turkish government regulations.
Stoltenberg spoke to reporters in advance of Thursday's meeting of alliance defense ministers in Brussels, where actions of the Russian military in Syria and any measures NATO needs to take as a result will be among the leading topics.
Stoltenberg said he was also concerned that in Syria the Russians are not targeting the Islamic State extremist group, "but instead attacking the Syrian opposition and civilians."