(Bloomberg) -- Two of Germany’s biggest airports suffered security breaches after climate protesters broke through the airfield’s security perimeter and glued themselves to aircraft taxiways.

Munich airport halted aircraft movements on its northern runway for about 45 minutes, the operator said in a statement, adding that there were no cancellations or “significant delays.” Police later removed the protesters from the taxiway, while managing to prevent a second intrusion attempt on the southern runway. In Berlin, protesters also managed to access a taxiway, though they were removed before causing any disruption, a spokeswoman for the airport said.

The protest marks the second time climate activists have penetrated security fences at Berlin airport in as many weeks, pointing to ongoing security vulnerabilities at the hub. 

READ: Berlin Runway Invasion Shows Hubs Vulnerable to Climate Protests

Letzte Generation, a group that argues governments, businesses and citizens aren’t doing enough to cut greenhouse gas emissions, issued a statement saying its activists were responsible. Letzte Generation was the group behind a break-in at Berlin that halted flights for several hours in late November. 

The latest incident underscores security weakness at German airports, particularly in Berlin. Monitoring the Berlin fence is the responsibility of the airport company, stopping unauthorized people from crossing the perimeter is a task for Germany’s federal police, who have previously warned that the split creates security vulnerabilities and sought to take on increased powers.

Flying is the most CO2-intensive form of travel, and while it accounts for around 2% of global emissions at present that’s likely to reach 22% by 2050, according to a European study, as air-passenger numbers increase and other industries make faster progress toward decarbonization.

©2022 Bloomberg L.P.