Alitalia flight attendants and air traffic controllers went simultaneously on strike Tuesday, causing the cancellation of some 400 flights.

Lufthansa had to cancel a total of 80 flights to and from Italy, affecting a total of 5,000 passengers, said Michael Lamberty, a spokesman for the Cologne-based company.

Also, British Airways and Air France were affected by the strikes.

Many AC Milan fans traveling to Athens ahead of Wednesday's Champions League final against Liverpool might be left stranded.

"Not allowing these people to fly poses a serious problem that could affect public order," the head of ENAC (Italian Civil Aviation Authority), Vito Riggio, said.

Officials summoned trade union representatives and Alitalia managers for the afternoon in an effort to determine who was to blame for the disruptions. Alitalia has put its 49.9 per cent stake in the company up for sale, creating a dispute with the trade union. The airline cancelled more than 350 flights due to a similar strike earlier this month and has been canceling dozens more on a daily basis over the past week. Alitalia, Europe's fifth-largest airline, is losing over 1 million euros ($1.35 million) a day as strikes and high fuel costs weigh.

Russian airline Aeroflot-Bank Unicredit; Italian investment bank Mediobanca and US investors Texas Pacific Group and Lufthansa partner Air One showed interest in the takeover. Binding offers must be presented July 2.