Senate Democratic leader Harry Reid said he would postpone a critical vote that had been scheduled for Jan. 24 "in light of recent events."
Lamar Smith, the Republican chairman of the House of Representatives Judiciary Committee, followed suit, saying his panel would delay action on similar legislation until there is wider agreement on the issue.
"I have heard from the critics and I take seriously their concerns regarding proposed legislation to address the problem of online piracy. It is clear that we need to revisit the approach on how best to address the problem of foreign thieves that steal and sell American inventions and products," Smith said in a statement.
The bills, known as PIPA (PROTECT IP Act) in the Senate and SOPA (Stop Online Piracy Act) in the House, are aimed at curbing access to overseas websites that traffic in pirated content and counterfeit products, such as movies and music.
The legislation has been a priority for entertainment companies, publishers, pharmaceutical companies and other industry groups who say it is critical to curbing online piracy, which they believe costs them billions of dollars a year.
But technology companies are concerned the laws would undermine Internet freedoms, be difficult to enforce and encourage frivolous lawsuits.
Public sentiment on the bills shifted in recent weeks after Internet players ramped up their lobbying.
White House officials weighed in on Saturday, saying in a blog post that they had concerns about legislation that could make businesses on the Internet vulnerable to litigation and harm legal activity and free speech.
Then on Wednesday, protests blanketed the Internet, turning Wikipedia and other popular websites dark for 24 hours. Google , Facebook, Twitter and others protested the proposed legislation but did not shut down.
The protest had quick results: Several sponsors of the legislation, including senators Roy Blunt, Chuck Grassley, Orrin Hatch, John Boozman and Marco Rubio, have withdrawn their support.
In a brief statement on Friday, Reid said there was no reason why concerns about the legislation cannot be resolved. He offered no new date for the vote.
Reid's action comes a day after a senior Democratic aide, speaking on the condition of anonymity, said the measure lacked the 60 votes needed to clear a procedural hurdle in the 100-member Senate.
The indefinite postponement of the bills drew quick praise from the Internet community, and ire from Hollywood.
"We appreciate that lawmakers have listened to our community's concerns, and we stand ready to work with them on solutions to piracy and copyright infringement that will not chill free expression or threaten the economic growth and innovation the Internet provides," a Facebook spokesman said.
Chris Dodd, chief executive of the Motion Picture Association of America and a former Democratic senator, said the stalling of legislation is a boost for criminals. "As a consequence of failing to act, there will continue to be a safe haven for foreign thieves," Dodd said.
