Apple has been accused of being among America's largest tax avoiders by a Senate committee. The committee said Apple has used a complex web of offshore entities to avoid paying billions of dollars in US income taxes. Apple chief Tim Cook will go before the panel tomorrow.In prepared testimony, Apple said it did not use tax gimmicks. The committee said there is no indication it has done anything illegal. Apple has a cash stockpile of 145 billion dollars, but the committee said 102 billion dollars of this was held offshore.The company says it is one of the largest taxpayers in the US, having paid 6 billion in federal corporate income tax in fiscal 2012.Some large firms in the US have come under fire for their reluctance to repatriate their foreign earnings as they could face a top tax rate of 35 per cent. US corporation tax is one of the highest in the world.