The European Union on Tuesday said US tech giant Apple must repay a record 13 billion euros ($14.3 billion) in back taxes after ruling that a series of Irish sweetheart tax deals were illegal.

"The European Commission has concluded that Ireland granted undue tax benefits of up to 13 billion euros to Apple. This is illegal under EU state aid rules because it allowed Apple to pay substantially less tax than other businesses. Ireland must now recover the illegal aid," a Commission statement said.