DUBLIN, March 12, 2013 (AFP) - No-frills airline Ryanair has placed an order for up to 200 Boeing planes worth $18 billion (€13.8 billion) at list prices, the Irish Independent said on Tuesday.

The order, set to be confirmed by US President Barack Obama and Irish Prime Minister Enda Kenny at the White House next week, is the single-biggest aircraft purchase ever agreed by Ryanair, the newspaper said.

Asked about the report, a Ryanair spokesman told AFP that the airline "does not comment upon, or engage in, rumour or speculation."

The order would be used to replace some existing 737 aircraft, while allowing the carrier to possibly extend its footprint beyond Europe, the paper said.

The report comes as Ryanair appeals a recent decision by the European Commission to block a third attempt by the airline to take over its Irish rival Aer Lingus over competition concerns.