The White House has described the European Commission's order for Apple to pay billions in back-taxes to Ireland as unfair, saying it amounted to a "transfer of revenue from US taxpayers to the EU".

White House Press Secretary Josh Earnest said that as the Irish Government had signalled its intent to appeal, he would not comment on the specifics but said it raised broader important principals.

He said the "kinds of payments contemplated by the EU" today amounted to "a transfer of revenue from US taxpayers to the EU" and that was the "crux" of the Obama administration's concerns about the "fairness of the approach".

Mr Earnest said the White House was concerned about a "unilateral approach" that threatened to undermine progress that had been made to try to make the international taxation system "fair".

He said they wanted to make sure that the system was fair "primarily to taxpayers" but also to companies trying to do business around the world, to "economies on both sides of the Atlantic".

Mr Earnest said the White House would continue to monitor the case and others being investigated by "the Europeans", but that there was "no reason" why they shouldn't be able to "make progress on a shared goal to prevent erosion of a tax base" to ensure taxpayers and businesses were "treated fairly".

He said that this issue of international taxation was something that got "a lot of attention behind the scenes inside the administration", and he said they were committed to fighting for fairness in the interest of taxpayers and businesses.

The White House also confirmed that Apple officials have been in contact with the Obama administration to report concerns about "how they are being treated by foreign governments".

Mr Earnest declined to say who exactly had been in touch from Apple and to whom they had spoken.

But he said that the Obama administration had repeatedly reiterated its "willingness to go and fight for" American taxpayers and American businesses overseas who were being "treated unfairly".

'US hopeful to continue working with European countries' - Psaki

Speaking to RTÉ News the White House Director of Communications Jen Psaki echoed Mr Earnest's words, saying that the White House wants to make sure that companies based in the US are treated fairly in their tax affairs abroad. 

Ms Psaki said that they were working with countries where taxation "would be an issue" to make sure that companies based in the United States were "treated fairly but that the American taxpayer never has to foot the bill".

She said they had been working for some time with international partners, including many European countries on international taxation and they were hopeful that progress would continue.

She said the White House would "obviously leave it to the leadership and the officials in Ireland to determine what the next steps are", adding that it was rare that US officials would speak about a case that was still open as this one was.

President Obama has spoken frequently about his desire to close the loopholes in the US tax code that permit US companies to take advantage of more favorable tax regimes elsewhere, and has previously singled out Ireland as a place where that happens.

Ms Psaki said that the foreign tax affairs of US multinational remained at the top of the President Obama agenda, through his final months in office.

She said tax affairs were "at the top of his discussions" and those of the Treasury Secretary, Secretary of State and other international partners.

Meanwhile, the US Chamber of Commerce in Washington DC has slammed the European Commission ruling on Apple's tax arrangements with Ireland, describing it as "egregious" and an "overreach".

The Chamber's Head of International Affairs Myron Brilliant said the ruling called into question the "ultimate legal authority" of European national tax regimes and threatened to drive away international investment.

He said today's ruling dwarfed previous rulings "tenfold" and fed a perception that the European Commission was "unfairly targeting US businesses".

Mr Brilliant said the Commission was using state aid rules to invalidate national tax laws retroactively, which was an example of "overreach".

He said businesses should not be "caught in the crossfire in a dispute between EU Member States and the European Commission".

Mr Brilliant said it was "telling" that the Irish Government planned to appeal a ruling that "ostensibly would add several billion Euros to its coffers".

He said that when today's ruling was taken alongside other investigations into US manufacturers, technology companies and service providers, it raised "significant new questions about Europe's attractiveness as an investment destination for US business".

The US Chamber of Commerce is a business federation representing companies, business associations, state and local chambers in the US, and American Chambers of Commerce abroad.