Amazon (AMZN  ) and its third-party sellers have been charging customers more for coronavirus pandemic essentials like face masks, toilet paper and antibacterial soap, according to a report from the consumer advocacy group Public Citizen.

The report demonstrates a pattern of price gouging, or increasing the price of a good to a level much higher than is considered reasonable in a time of high demand, on products listed to be sold both by Amazon and third-party merchants on the e-commerce platform throughout the pandemic.

Researchers tracked the prices of 15 essential consumer product sold on the website during the coronavirus pandemic against their recent prices on Amazon and other national retailers. The report details how products like a "pack of eight 1000-sheet toilet paper rolls" and a "pack of 50 disposable face masks" had markups by 528% and 1,000%, respectively.

Another item tracked, a 7.5 ounce bottle of Dial-brand hand soap, was available on Amazon for $6.41, but other sellers like Target (TGT  ) had priced the product at $1.49, while CVS Health (CVS  ) listed it as $2.29, according to Bloomberg News.

At the start of the coronavirus outbreak in the United States, every governor had declared a state of emergency, with some states offering legal protection for consumers against the practice of price gauging by retailers. While price gauging is illegal in a majority of states, the chaos of the pandemic seemed to let it go unchecked on the internet as consumers rushed to gather essentials amid heightened uncertainty.

In the consumer demand craze, Amazon had come out against price gouging after reports had charged the e-commerce platfrom of the practice. The retail giant blamed the higher prices on in-demand products on third-party sellers, according to a CNBC report published in February. The company stated that its "Fair Pricing Policy," prohibited the practice and affirmed that it would remove merchants who violate the policy from the platfrom.

However, the Public Citizen report states that Amazon and its third-party sellers continued to raise prices on essentials despite the e-commerce platform having polices against it.

"Amazon has fundamentally misled the public, law enforcement and policy maker about price increases during the pandemic," said Alex Harman, competition policy advocate for Public Citizen and author of the report, in an article accompanying the report.

"Amazon has publicly blamed third party sellers for price increases while continuing to raise prices on its own products and allow those sellers to increase their prices. The facts demonstrate the need for a federal price gouging law and for Amazon to implement major reforms to its pricing and products listing practices," Harman added.

Amazon has denied the claims made in the Public Citizen report, with a spokesperson telling Bloomberg News: "There is no place for price gouging on Amazon and that includes product offered directly by Amazon. Our systems are designed to offer customers the best available online price, and if we see an error, we work quickly to fix it."