Members of the public in Denmark have recorded over 500 possible drone sightings in the past 24 hours, after Scandinavia was targetted in a series of aerial attacks that some European officials have linked to Russia.

The population is full of fear following the drone incursions that shut down two of the country's airports on Wednesday night in what has been described by officials as a 'systematic operation' and a 'hybrid attack'. 

It was the second incident in two days following Monday night's drone disruption over Copenhagen airport that interfered with around 100 flights and left 20,000 passengers stranded.

As officials continue to investigate who the 'professional actor' behind the attacks might be, civilians in Denmark are anxiously looking up at the skies in anticipation of more unwanted aerial incidents.

The police are yet to confirm any of the 500 reported sightings, but are encouraging Danes to keep their eyes peeled and provide the authorities with detailed descriptions of anything they might see, reported TV 2. 

It comes as European ministers are scrambling to draw up plans for a continent-wide 'drone wall' to counter Moscow's aerial incursions, as the Kremlin warns that any strike on its aircraft would result in direct conflict with NATO. 

Nations including Denmark, Finland, Poland and the Baltic states will join Ukraine at a summit today to thrash out plans for what EU chief Ursula von der Leyen has described as 'the bedrock of credible defence.' 

The Kremlin has been accused of launching a campaign of hybrid attacks across Europe, exposing the vulnerability of the continent's airspace at a time of high tensions between Moscow and NATO.

Poland, which has already brought down Vladimir Putin's drones in recent weeks, has vowed it will down any hostile objects over Ukraine under fast-tracked laws giving the military greater freedom to act.

However, in a chilling escalation, Russia's ambassador to France warned that shooting down its planes 'would be war.' On Thursday, the country's foreign minister also accused NATO of waging 'real war' on it and claimed the organisation was directly involved in its conflict with Ukraine. 

The ministers' meeting in Brussels is expected to focus on creating joint systems to detect and destroy drones that threaten civilian and military infrastructure. 

The European Commission has indicated that the cost of the wall could be covered by its €150bn Security Action for Europe loans scheme. 

Danish defence minister Troels Lund Poulsen said his country had already been targetted after multiple airports were disrupted by drones on the same night. 

The incursions forced Aalborg airport, used for commercial and military flights, to shut for three hours, while Billund airport, Denmark's second-largest, was closed for an hour.

Drones were also seen near Esbjerg and Sonderborg airports, as well as Skrydstrup airbase, home to Denmark's F-16 and F-35 fighter jets, and over a military facility in Holstebro.

Poulsen said: 'There can be no doubt that everything points to this being the work of a professional actor when we are talking about such a systematic operation in so many locations at virtually the same time. 

'This is what I would define as a hybrid attack using different types of drones. This is an arms race against time because technology is constantly evolving.'

Danish prime minister Mette Frederiksen has spoken to NATO secretary general Mark Rutte about 'the serious situation related to drones over Danish airports.' 

Rutte said: 'NATO allies and Denmark are working together on how we can ensure the safety and security of our critical infrastructure.' 

Officials concede that spotting drones is a huge challenge. Commission spokesman Thomas Regnier said: 'One thing that we will have to do is detect these incoming drones. This is not super-easy to do. 

'We're not talking about big fighter jets and planes coming in. No, we are talking about the latest technology developments. These drones have to be detected, and then, second track [will be to decide] what will we do to fight back against these drones.'

Police in Denmark are investigating whether some of the drones were launched from ships off the coast, with two Russian vessels seen in the area at the time.

 Moscow's embassy in Copenhagen dismissed suggestions of involvement as 'absurd' and described the incidents as a 'staged provocation' designed to escalate tensions. 

Justice minister Peter Hummelgaard warned that 'the threat from hybrid attacks is here to stay' and described the recent events as 'deeply worrying incidents across Europe.' He said new laws would give infrastructure owners the right to bring drones down themselves.

While Europe debates new defences, Polish prime minister Donald Tusk has warned 'the situation brings us the closest we have been to open conflict since World War Two' and confirmed that Warsaw will act if its skies are violated. 

He said: 'We will take the decision to shoot down flying objects when they violate our territory and fly over Poland - there is absolutely no discussion about that.' 

Earlier this month, Poland shot down three Russian drones that crossed into NATO territory, the first time such action has been taken since the full-scale invasion of Ukraine began in 2022. 

Tusk said Poland would also remain cautious in more ambiguous cases. 

He said: 'When we're dealing with situations that aren't entirely clear, such as the recent flight of Russian fighter jets over the Petrobaltic platform - but without any violation, because these aren't our territorial waters - you really need to think twice before deciding on actions that could trigger a very acute phase of conflict.' 

He added: 'I also need to be absolutely certain… that all allies will treat this in exactly the same way as we do.'

The threat of escalation has been underscored by Moscow. Alexey Meshkov, Russian Ambassador to France, told RTL: 'You know, there are many NATO planes that violate Russian airspace, deliberately or not, but it happens quite often. They are not shot down afterward.'

Denying Russia was behind the drone attacks, he added: 'Russia doesn't do that, play with anyone. It's not really our thing.' He claimed the West had 'fooled' Moscow 'on many occasions'.

Asked about the possibility of NATO bringing down Russian planes, he chillingly said: 'It would be war.' His words came after US president Donald Trump told the United Nations that NATO states could shoot down Russian aircraft if they intruded on their airspace.

Meanwhile, speaking at the G20 foreign ministers summit on Thursday, Sergei Lavrov said: 'Another clear example is the crisis in Ukraine provoked by the West, through which NATO and the EU have... already declared a real war on my country and are directly involved in it.'

The sense of crisis has grown across the continent. Estonia reported three Russian fighter jets entering its skies last Friday, while Romania said one of its border areas was struck by a drone days earlier. 

European officials called these moves deliberate provocations intended to unsettle NATO. With peace efforts going nowhere, many fear the conflict in Ukraine could spill over into neighbouring countries at any moment.

Britain has also been drawn in - the Royal Navy dispatched HMS Iron Duke and a Wildcat helicopter to shadow the Russian frigate RFN Neustrashimy and the cargo ship Sparta IV through the Channel. 

Defence minister Luke Pollard said: 'Russian warships are increasingly transiting through the English Channel. 

The Royal Navy protects the UK 24/7 to monitor Russian movements, ensuring the security of our waters and undersea cables. Alongside our commitment to NATO's Eastern Sentry, this is a clear demonstration of how the UK stands firm with our NATO allies to deter Russian aggression.'

Across Europe, officials believe the Kremlin is deliberately walking a tightrope, staging incidents that fall short of an outright attack but still force NATO to respond.