near-collision between a passenger jet and a Russian spy plane was among dozens of “highly disturbing” recent encounters between Moscow and the West, according to a report by a think tank’s published Monday. The study by the European Leadership Network comes days after NATO warned of a spike in Russian air activity over European airspace. The ELN said there have been almost 40 “sensitive incidents” — a return to Cold War levels — since political upheaval erupted in Ukraine eight months ago.

“To perpetuate a volatile stand-off between a nuclear-armed state and a nuclear-armed alliance and its partners … is risky at best,” said a statement accompanying the report. “It could prove catastrophic at worst.” Reacting to the report, British General Sir John McColl said: “The potential for error and escalation is clear, and extremely dangerous.” NATO’s former deputy supreme allied commander in Europe told the Guardian newspaper it was “more a matter of when rather than if.”

The ELN reported highlighted that a Scandinavian Airlines (SAS) Boeing 737 being forced to take evasive action during takeoff after it came within about 90 yards of a Russian reconnaissance plane. The incident, which was confirmed to NBC News by the airline, happened while the jet carrying 132 people was en route from Copenhagen to Rome on March 3.