Fresh threats have been levelled at air traffic at Denmark’s Copenhagen airport and flights from the Czech Republic, Italy and France.
Danish police said on Friday that they are on the scene at Copenhagen airport and investigating.
A spate of bomb threats has caused disruption to passenger flights across Europe over recent days.
The threats have forced diversions, emergency landings and security sweeps, but no explosives have been found so far.
"We are once again at Copenhagen Airport today in connection with threats directed at air traffic," police said in a statement on Friday.
"We are now investigating the incident and have a visible presence at the airport."
Copenhagen Airport in an emailed statement confirmed the police presence and said the airport was "operating normally". A spokesperson declined to comment further.
Police said that their immediate assessment was that there was not any danger to passengers or anyone else at the airport.
Meanwhile, the French prime minister’s office said that four new bomb threats had been made against planes flying over French territory on Friday. All had landed safely.
A Wizz Air flight between Prague and Rome was also diverted to Venice due to a bomb scare, an airport authority source said.
Czech police said they had registered bomb threats to flights departing from and arriving in Prague.
An airport spokesperson said they concerned four inbound and five outbound flights, but that no explosive devices had been found and no flights had been cancelled or diverted as a result.
A bomb alert on a Ryanair flight from Rome to Lisbon prompted a security operation when it landed, CNN Portugal reported.
Two UK airports, Heathrow and Birmingham, received bomb threats earlier this week, while several flights out of the UK were also targeted, including flights from London Stansted, Newcastle and Glasgow.
Read more: Are travellers affected by bomb threats eligible for compensation?
Two Ryanair flights from Dublin and Lisbon were also searched following anonymous tips regarding potential bomb threats, and an airport in Poland was closed while investigations were carried out.
More than a dozen flights were targeted on Thursday, included those from Copenhagen, Dublin, Helsinki, Madrid, Milan and Warsaw.
A military bomb disposal unit searched two planes at Copenhagen on Thursday.
The government has said it believes threats made to UK airports and flights were “malicious hoaxes”.
They have prompted serious concerns over the threat of information warfare, during a week that has also seen cyber attacks on supermarket fridges and blood banks in Europe.
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