Russian involvement in the 4½-year-old Syrian civil war seems to be escalating, with NATO's secretary general confirming Tuesday a second incursion by Russian planes into Turkish airspace and saying Russian ground troops were in Syria as well.
"It's unacceptable, it's dangerous, and it's reckless behavior and it adds to the tensions," Secretary General Jens Stoltenberg told CNN about the incursions into Turkish airspace.
"We see the violation of the Turkish airspace becomes more important, more dangerous, because it happens in a context where we see more fighting, more Russian military presence in Syria."
Stoltenberg expressed alarm over how the Russian military grows on several fronts in Syria.
"So we have seen a substantial military buildup by Russia in Syria, both in the air with the combat planes and air defense systems, but also an increasing number of ground troops," he said. "In addition to that, they have deployed naval assets, a large number of naval assets close to the Syrian shores. And they continue to do so."