Lithuania – a strategically important Nato-member for securing the Baltic – has declared a state of emergency over security posed by Russia-allied Belarus.

Vilnius International Airport was again forced to close over balloons,which the government says were deployed by smugglers transporting cigarettes in recent weeks.

Thousands of passengers were stranded as Europe remains on alert over recent intrusions into Nato airspace during the war in Ukraine.

Prime minister Inga Ruginien warned: ‘In combating the Belarusian hybrid attack,we must take the strictest measures and defend the areas most affected by this attack.’

The announcement followed a Cabinet meeting of the Baltic state,which is a strong backer of Ukraine in its fight against Russian forces.

The national emergency means the army will be able to patrol the border area together with other uniformed services and receive extra rights from parliament,such as to conduct searches or detain people.

While the balloons are used to smuggle cigarettes into Lithuania,officials see their numbers and trajectories as deliberate acts of disruption orchestrated by Belarus.

According to the Lithuanian government,the Vilnius International Airport has been closed for more than 60 hours since October due to the threat posed to civil aviation.

Lithuanian border guard officers during a patrol along the Belarus-Lithuania border (Picture: Getty)

More than 350 flights and approximately 51,000 passengers have been affected altogether.

Interior minister Vladislav Kondratovi’ said Lithuanian prosecutors have launched an investigation into the balloons and the secret services would provide information about the connection with the neighbouring regime.

He said: ‘I have no information that the Belarusian side is trying to curb the senders of the balloons. And this is one of the proofs that this is a hybrid attack.’

In October, Lithuanian authorities closed two border crossings in response to the airspace violations.

Lithuania has drawn up plans to shut its border crossings with Belarus indefinitely (Picture: Getty)

Responding from Belarus,authoritarian president Alexander Lukashenko denounced Lithuania’s move to close the border as a ‘mad scam’.

He said it was part of a ‘hybrid war’ against his country and suggested that Lithuania needs to combat smuggling of contraband.

The balloons could not harm civil aviation,he claimed,and instead,the Belarusian leader accused Vilnius of ‘politicizing’ the problem.

‘Of you want normal relations,sit down at the table and discuss these issues. We are ready to do that,’ Lukashenko said during a session of Belarus’ security council.

Belarus’ deputy foreign minister Igor Sekreta also urged Lithuania to meet at the negotiating table,saying: ‘For some reason, Lithuania perceives any contact at a political level with the Belarusian side as a defeat.’