Police at Austrian airports are on alert as environmental activists pledge to stage protests at airports worldwide on Wednesday.

At Vienna Airport, four members of the “Last Generation” movement staged a demonstration in the check-in area of Terminal 3 around midday, holding signs that read ‘Oil Kills’ and spilling orange paint. Passenger traffic was not disrupted.

“Airport staff responded promptly and redirected passenger flows,” said police spokesman Raimund Schwaigerlehner. The group faces charges under administrative law for holding an unauthorised assembly and causing a public disturbance. Additionally, they are suspected of criminal damage.

The “Last Generation” movement stated that the paint used was water-soluble gouache, which can be removed without leaving any residue.

Earlier in the day, air traffic was disrupted at Cologne/Bonn Airport for several hours after five individuals from the “Last Generation” group glued themselves to the tarmac to highlight aviation’s contribution to climate change. According to Cologne police, charges have been filed for violations of assembly laws, dangerous interference with air traffic and trespassing. The runways were reopened by 9.20am.

A protest also took place at Zurich Airport in Switzerland, where a group of activists briefly blocked the road to the airport before being rounded up by police. The activists were part of the group “Act Now!”, which is affiliated with “Extinction Rebellion”. The action was aimed “against a government that remains inactive in the face of the worsening climate crisis,” according to the movement.

Similar protests at airports have been announced by climate activists for the UK, the Netherlands, Canada, the USA, Scotland and Norway on Wednesday.