The chief executive of Apple has dismissed the EU’s tax ruling as “political crap” and said Ireland was being “picked on”, as he vowed to push ahead with expansion plans in Cork.

In an interview with the Irish Independent, Tim Cook suggested the European commission might be trying to use state aid rules to harmonise tax rates across the EU.

“There are other possibilities too, but I think it’s clear that there is a desire to harmonise tax rates across the EU. Doing it this way doesn’t seem like the right approach to me. There should be a public discussion about it.”

He rejected the assertion by European competition commissioner, Margrethe Vestager, who conducted a three-year investigation into the iPhone maker’s complex tax dealings, that Apple paid just 0.005% tax in Ireland in 2014. She said Apple’s sweetheart tax deal with Ireland constituted illegal state aid.

“It’s total political crap,” Cook said. “They just picked a number from I don’t know where. In the year that the commission says we paid that tax figure, we actually paid $400m. We believe that makes us the highest taxpayer in Ireland that year.”

The Apple boss said he would “love” to see the Irish government appeal against the commission’s ruling to pay €13bn (£11bn) in back tax to the Irish government.

“I think we’ll work very closely together, as we have the same motivation. No one did anything wrong here and we need to stand together. Ireland is being picked on and this is unacceptable.”

Ireland’s governing coalition government is split over whether it should immediately appeal against the commission’s ruling. Further talks are planned before it will make a decision. The Irish finance minister, Michael Noonan, is one of the strong backers of an appeal, and has insisted that the country needs to preserve its status as a low-tax base for overseas companies.

Vestager said Apple had improperly routed taxable income to a head office that only existed on paper and could not have generated such profits. However, Cook insisted that Apple and Ireland had “played by the rules” and would win the case on appeal. He warned this could escalate into a trade row between the EU and US.

“I think that Apple was targeted here,” he said. “And I think that [anti-US sentiment)] is one reason why we could have been targeted.”

Cook said Apple paid income tax of 26.1% globally. “Some people would say that that should be higher and some might say it should be lower. I’d be the first to say that the tax system needs to be reformed and that it should be made simple and straightforward. But it should be talked about going forward, not in a way that retrofits the law to what others wish it was.”

The tech firm is pressing ahead with plans for expansion in Cork. Cook said: “We have a 37-year-old marriage with Ireland and it means something to us … I feel like Ireland stuck with Apple when it wasn’t easy to stick with Apple, and now we’re sticking with Ireland.”