Sen. Bernie Sanders said it's a "disgrace" that Amazon and Netflix don't pay their fair share of tax under Donald Trump's tax bill, at a Fox News townhall event on Monday.

The Democratic presidential candidate released his own tax returns going back 10 years on the same day.

Sanders has been a vocal critic of Amazon in the past.

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Sen. Bernie Sanders renewed his attack on retail behemoth Amazon on Monday, with Netflix drawing his ire as well.

Speaking at a Fox News town hall event, Sanders criticised the way America's tax system allows corporate giants to pay small amounts of tax.

"I happen to believe… that we have an absurd tax system," Sanders told Fox News hosts Bret Baier and Martha MacCallum.

"While millions of people today are paying actually more in taxes than they anticipated, Amazon, Netflix and dozens of major corporations, as a result of Trump's tax bill, pay nothing in federal taxes. I think that's a disgrace," he said. On Monday Sanders also released his own tax returns, going back 10 years.

Sanders has a history of needling Amazon, taking the company to task over its working conditions. He aggressively lobbied the company to raise its minimum wage, which it did in November of last year.

Neither Amazon nor Netflix paid any federal or state income tax 2018, although they made $11.2 billion and $845 million in profit respectively.

In response to Sanders' comments, an Amazon spokesman told Business Insider:

"Amazon pays all the taxes we are required to pay in the U.S. and every country where we operate, including paying $2.6 billion in corporate tax and reporting $3.4 billion in tax expense over the last three years. Corporate tax is based on profits, not revenues, and our profits remain modest given retail is a highly competitive, low-margin business and our continued heavy investment."

He also pointed to Amazon's investments in the US, and the over 250,000-strong workforce it employs in the country. Netflix was not immediately available for comment when contacted by Business Insider.

Read more: Bernie Sanders renewed his war with Amazon over working conditions for its lowest paid employees

Sanders isn't the only one to criticise Amazon's minimal tax bill.

After CEO Jeff Bezos published his letter to shareholders last week, in which he challenged rival retailers to up their minimum wage to $16 per hour — $1 more than Amazon's minimum wage which came into force in November — Walmart clapped back.

"How about paying your taxes?" tweeted Walmart's executive vice president of corporate affairs Dan Bartlett.

A recent report from the Institute on Taxation and Economic Policy said Amazon used "tax loopholes that allow profitable companies to routinely avoid paying federal and state income taxes."