“We have already reduced flights by 10 percent to Sardinia and we will do the same for Sicily this winter,” O’Leary said on Tuesday, amid an ongoing row between budget airlines and the Italian government over a new law aimed at limiting air fares to and from the islands.

“It is a stupid, idiotic decree, which will reduce flights by increasing fares,” O’Leary said as he presented the company’s winter routes, adding that it was “based on rubbish data.”

Ryanair, which has repeatedly criticised the move since it was first announced in August, had already announced an eight-percent reduction in services to and from the island region of Sardinia.

“A reduction of almost 10 percent compared to the planned schedule is entirely linked to the Italian government’s decree, which we consider totally illegal and which will only have the effect of reducing connectivity,” Ryanair Chief Commercial Officer Jason McGuinness told reporters in Cagliari on Thursday.

READ ALSO: What does Italy’s new flight price cap mean for passengers?

McGuinness on Thursday appealed to Italy to “stop this decree law to avoid further irreparable damage and, instead, make Italy more competitive by removing the municipal surcharge tax from all the airports on the peninsula.”

The cut means the cancellation of three domestic routes: between Trieste and Cagliari, and between Alghero and Treviso, and Alghero and Bari. It lowers the number of connections on seven routes including six important connections to Rome, Milan (Bergamo and Malpensa), Catania, Naples and Venice, as well as Brussels Charleroi.

Italy’s government said the decree will clamp down on the use of algorithms to set flight prices, which have been blamed for soaring fares to the major islands.

The decree bans the algorithms if applied to connections to Sicily and Sardinia; if applied to peaks in demand linked to seasonal factors; and if they lead to the price of tickets or services being 200 percent higher than the average price.

Asked about O’Leary’s comments on Tuesday, Italy’s business minister told reporters: “Italy is a sovereign country and won’t be blackmailed.”

Urso denied accusations that the decree was illegal, and said Ryanair “has been punished 11 times for having breached the market rules and the rights of consumers of this country.”

The decree has yet to become law, and Urso has held a series of meetings with airline bosses ahead of its implementation.

Flights between mainland Italy and the islands have repeatedly been flagged up by consumer groups as being overpriced, and airlines have long faced accusations of running a “price cartel”: something Ryanair has furiously denied.

The European Commission said it had sought clarification from Rome over the decree, adding that price capping is rarely an effective way to achieve affordable prices.