Vladimir Putin is being blamed for a series of drone incursions that shut down airports in two NATO capital cities and led to massive disruptions to flight traffic. Air traffic controllers in Copenhagen shut down arrivals and departures for a space of roughly four hours late Monday night,

Ukraine's leader to push for "robust action" against Russia at U.N. gathering, as America's NATO partners accuse Putin of dangerous incursions, and lies.

Europe is said to be preparing for war following the rising tensions between NATO and Russia. A German general recently claimed that if a war with Russia were to begin, we would be seeing a daily death count on the battlefield that wouldn't have been seen in decades.

While the air and ground war in Ukraine grinds on, Moscow is increasing pressure on Kyiv’s western allies. Russian drone incursions into Poland in the early hours of September 10, and Romania a few days later, were followed by three Russian fighter jets breaching Estonian airspace on September 19.

Russia is reportedly keeping back some new recruits in order to create a pool of soldiers that could be used in a conflict with the West.

"We know that Russia is going to move forward," Lithuanian Defense Minister Dovile Sakaliene told ABC News by video call during her visit to Kyiv last weekend.

In the years since Russia invaded Ukraine, NATO has focused on defending its own territory first and resisted lower-level harassment from Russia, like acts of sabotage and intimidation.

Two Eurofighters were on Sunday morning tasked to investigate an unidentified Russian IL-20m military aircraft that had entered neutral airspace over the Baltic Sea, Germanys air force said