More NATO countries will move troops and fighter jets eastwards after more than a dozen drones entered Polish airspace on Wednesday.

Denmark, France, and Germany have joined a new mission to bolster the military alliance's eastern flank. Other NATO allies are expected to take part later.

Tensions have been high across Europe since Poland accused Russia of an unprecedented incursion. Some of the 19 drones that entered Polish territory were shot down, while others crashed into fields and even a house in eastern Poland.

Warsaw said the incursion was deliberate, but Moscow downplayed the incident, saying it had no plans to target facilities in Poland.

Drones and missiles have occasionally veered into countries bordering Ukraine, including Poland, during Russia's full-scale invasion - but this was the most serious incident of its kind since the war began in February 2022.

Polish Prime Minister Donald Tusk said it was the closest we have been to open conflict since World War Two.

Denmark will contribute two F-16 fighter jets to support Poland's air defense, as well as a warship, its defense ministry said.

Danish Prime Minister Mette Frederiksen said: We must not be naive. Putin will stop at nothing, and he is testing us. Therefore, it is crucial... Denmark is contributing to this. France has already said it will contribute three Rafale fighter jets, and Germany has pledged four Eurofighters.

The UK is fully committed to help strengthen the Eastern Sentry operation, the Ministry of Defence said.

On Friday, European countries and the US backed Poland during an urgent UN Security Council session in New York discussing the incursion.

Acting US Ambassador to the UN Dorothy Shea stated, The United States stands by our NATO allies in the face of these alarming airspace violations... we will defend every inch of NATO territory. She emphasized that Moscow had intensified its bombing of Ukrainian cities since a recent summit with US President Trump.

While Kremlin officials maintained that the drones were not targeted at Poland, tensions remain high as military drills between Russia and Belarus continue near the borders of Poland and Lithuania.

This situation underscores the increasingly volatile security landscape in Eastern Europe and the significance of NATO's collective defense commitments.