Russia's drone incursions and airspace violations of European NATO members have increased since September, when more than 20 Russian drones entered Polish airspace and three Russian military aircraft violated Estonian airspace for 12 minutes, Reuters reported.
Since then, numerous drone overflights, mostly of unknown origin, have disrupted airspace operations in Europe.
European Commission President Ursula von der Leyen called the incursions "hybrid warfare" and while she did not say Russia was responsible for all the incidents, she stressed that it was clear that Russia's goal was to "sow division" in Europe.
Here are some of the biggest airspace violations and drone sightings reported since the beginning of the year.
The map shows drone sightings and airspace violations in Europe by Russia, Belarus or unknown entities so far:
BELGIUM
The airports in Brussels and Liège were closed yesterday evening after drones were spotted. This diverted many arriving planes and prevented others from taking off. Brussels Airport reopened this morning, although some flights were canceled and others delayed.
Belgian Defense Minister Theo Francken said Sunday that police were investigating drone sightings over the "Kleine Brogel" air base. in northeastern Belgium.
Brussels launched an investigation last week after two drone sightings over a military base in the southeast of the country and another investigation last month after several drones were seen flying over a military base in Elsenborn, on the German border.
CZECH REPUBLIC
The Czech army said on September 10 that it was detecting a growing number of unidentified drones over its military facilities, according to the Institute for the Study of War research group.
DENMARK
Drones disrupted air traffic at six Danish airports in September, including Copenhagen - the busiest airport in the Nordic region - in what Prime Minister Mette Frederiksen called a hybrid attack on her nation.
ESTONIA
Three Russian military aircraft violated the airspace of the NATO member Estonia for 12 minutes on September 19, before Italian Alliance fighter jets escorted them out.
GERMANY
Airports in Berlin and Bremen were briefly closed over the weekend after two separate drone sightings.
Drones were spotted at airports and military installations in Germany earlier in October. A police report noted that the sightings at Munich Airport on October 3 were just the tip of the iceberg.
The interior ministry of the German state of Schleswig-Holstein said on September 26 that drones had been spotted overnight and were being investigated for possible espionage and sabotage.
LITHUANIA
NATO member Lithuania closed Vilnius Airport and border crossings with Belarus on October 28 after several objects identified as possible helium balloons entered its airspace. It was the fourth such incident in a week.
On October 23, the country said that two Russian military aircraft had entered its airspace for about 18 seconds, prompting an official protest and a response from NATO forces, while Russia denied the incident.
NORWAY
Norway's Oslo Airport temporarily suspended several landings early on the morning of October 6 after a report of a drone being intercepted near the airport, its operator Avinor said.
POLAND
On October 30, Polish MiG-29 fighter jets intercepted a Russian reconnaissance plane over the Baltic Sea, Polish Defense Minister Wladyslaw Kosińska-Kamiś said.
The country's military said that its planes had intercepted a Russian plane carrying out a reconnaissance mission in international airspace over the Baltic Sea on October 28. October.
About 20 Russian drones entered the country's airspace on the night of September 9-10. NATO deployed F-35 and F-16 fighter jets, helicopters and the Patriot air defense system to respond to the incursion.
ROMANIA
Romania scrambled fighter jets on September 13 when a drone violated the country's airspace during a Russian attack on Ukrainian infrastructure near the border.
SPAIN
Flight operations at Palma de Mallorca airport were temporarily suspended on October 20 after drones were spotted.