Google has hit back at Rupert Murdoch after he branded the search giant a "piracy leader".
The News Corporation chairman tweeted that Google "streams movies free" and "sells [adverts] around them".
In response, Google said that it fought pirates and counterfeiters "every day".
Mr Murdoch was tweeting in response to the White House's apparent opposition to some aspects of the controversial Stop Online Piracy Act (Sopa).
If passed, the act would give content owners and the US government the power to request court orders to shut down websites associated with piracy.
Some opponents to Sopa are set to partake in an internet "blackout" on 18 January, temporarily removing access to their sites.
Wikipedia founder Jimmy Wales said on Monday the website would be "protesting bad law" on Wednesday.
Recommendation site Reddit is also said to be on board with the protest.
'Silicon Valley paymasters'
However, the bill's main opponent in Congress, Republican Representative Darrell Issa, is now reported to have said the bill would not be brought to a vote in the House of Representatives.
"I am confident that flawed legislation will not be taken up by this House," Mr Issa said in a statement, citing assurances from House Majority Leader Eric Cantor.
"Majority Leader Cantor has assured me that we will continue to work to address outstanding concerns and work to build consensus prior to any anti-piracy legislation coming before the House for a vote."
On Saturday, a statement from the White House appeared to side with critics of both Sopa and Protect IP Act (Pipa) - a similar bill due to be put before the Senate.
In response to an anti-Sopa petition, the White House said online piracy needed a "serious legislative response" but that it must not "inhibit innovation".
It added: "We will not support legislation that reduces freedom of expression, increases cybersecurity risk, or undermines the dynamic, innovative global internet."
The stance is likely to anger many companies who have publicly supported Sopa.
Among them is News Corporation. Mr Murdoch's Twitter comments accused the Obama administration of bowing to "Silicon Valley paymasters".
"Piracy leader is Google who streams movies free, sells [adverts] around them. No wonder pouring millions into lobbying," the 80-year-old wrote.
He was referring to Google's indexing of sites offering illegal downloading of movies and other copyrighted content.
To back up his complaint, he later added: "Just been to google search for mission impossible. Wow, several sites offering free links. I rest my case."
Google told technology website Cnet that Mr Murdoch's comments were "nonsense".
A spokeswoman told the BBC: "Google respects copyright - and we've worked hard to help rights holders deal with piracy.
"Last year we took down five million infringing web pages from our search results and invested more than $60 million (£40m) in the fight against bad ads."
Google, an opponent of Sopa, said it believed there are better methods of protecting against copyright infringement.
The company suggested "targeted legislation that would require ad networks and payment processors - like ours - to cut off sites dedicated to piracy or counterfeiting".
Backers of the bill say it will make it easier for content creators to protect their copyrighted material in the face of online piracy.
However, critics say it will hinder freedom of speech and innovation on the internet.
If further debate on Sopa continues this month, it is still unlikely a vote will be passed before the US presidential elections in November.