NATO member Lithuania reported that two Russian military aircraft briefly entered the country’s airspace on October 23, remaining inside for roughly 18 seconds.
The aircraft, a Su-30 fighter jet and an Il-78 refueling tanker, appeared to be conducting a refueling training mission when they crossed into Lithuania's airspace from Russia’s Kaliningrad region. In response, NATO's Baltic Air Policing dispatched two Spanish Air Force Eurofighters to intercept the jets and patrol the area.
Once a more cooperative partnership, ties between the North Atlantic Treaty Organization and Moscow have deteriorated sharply, today resembling the tense standoff of the Cold War. NATO leaders view Russia as a direct security threat, but repeated warnings and condemnations from the Alliance have so far had little effect on the Kremlin.
So, how has a previously constructive relationship between NATO and Russia turned so fractious? Click through this gallery and find out more about why Russia fell out with NATO.