British Airways parent International Airlines Group confirmed the purchase of Irish carrier Aer Lingus on Tuesday, saying offers for 96 percent of its share capital had been accepted.

IAG, which also owns Spain's Iberia, confirmed its offer had been accepted by Irish carrier Ryanair, which had owned 29.8 percent of the former Irish flag-carrier.

"Ryanair's acceptance was a condition of the offer which is now wholly unconditional as all the conditions have been satisfied," IAG said in a statement.

Now with 95.77 percent of Aer Lingus' share capital, the group urged remaining shareholders to accept the offer by September 1.

"We'd like to welcome Aer Lingus into IAG," said the group's chief executive Willie Walsh.

"It will remain an iconic Irish brand with its base and management team in Ireland but will now grow as part of a strong, profitable airline group."

IAG offered guarantees to the Irish government in order to secure the deal, including maintaining the Aer Lingus brand and existing routes, and creating new jobs.

The deal was backed by the European Commission last month, subject to conditions aimed to address concerns over competition.