COPENHAGEN, Denmark (AP) — Police in Denmark and the Czech Republic investigated threats to air traffic on Friday, while a Romanian plane received a bomb threat following a string of hoaxes that have targeted flights and disrupted travel across Europe this week.

A flight from Prague to Bucharest operated by Romanian carrier Tarom received a bomb threat. The plane landed at its intended destination, and airport administration officials said the bomb threat proved to be false.

In the Danish capital, Copenhagen, police said Friday they were present at the airport for a second consecutive day “in connection with threats directed at air traffic.” They said their immediate assessment was that there had been no danger to passengers or to others at the airport. It added that air traffic was proceeding safely and without disruption.

Czech police also said they were again dealing with threats against planes on Friday. They said necessary security measures have been taken in cooperation with Prague’s Vaclav Havel Airport that have “a minimal impact on the normal operations at the airport.”

Meanwhile in Ireland, the Dublin headquarters of national broadcaster RTE was evacuated Friday after a bomb threat, and live broadcasts were replaced with pre-recorded programs.

Ireland’s police force, An Garda Síochána, said it was ”aware of a threat made against media organisations here and in Europe.” It said that it has been liaising with Irish media organizations and the threat will be investigated.

More than two dozen flights were affected by threats earlier in the week, with some diverted as authorities scrambled to rule out any danger.

Europe has experienced a slew of other disruptions recently, such as attacks on supermarket refrigeration systems, drone incursions and mysterious triggers to alert apps.

Fake bomb threats are relatively common but it is unusual to see so many in such a short period. They come at a time of increased geopolitical tensions and warnings from authorities that Russia may be ramping up so-called hybrid threats in Europe.