Several lawmakers expressed support Wednesday for a controversial bill aimed at curbing online piracy as lobbying over the issue reached a fever pitch.

In a House Judiciary Committee hearing on a bill proposed by committee Chairman Lamar Smith (R-Tex.), a bipartisan group of lawmakers said new laws are needed to help media outlets, software makers and retailers fight the illegal distribution of movies, songs and software.

Smith’s Stop Online Piracy Act is aimed at foreign sites dedicated to pirated material, but Web giants such as Google and Facebook and telecommunications firms say his proposal goes too far, making them responsible for shutting down bad actors.

“The problem of rogue Web sites is real, immediate and widespread. It harms all sectors of the economy,” Smith said during the hearing.

Several lawmakers expressed concern that the illegal exchange of copyrighted movies, software and music is draining U.S. media companies and that current laws don’t give law enforcement enough power to stop bad actors.

And some questioned the motives of Web giants fighting the legislation.

Opposition is “really about the bottom line,” said Rep. Mel Watt (D-N.C.). “Sites that specialize in stolen goods attract lots of users and lots of ads.”

Supporters and critics of the measure ramped up their lobbying efforts ahead of the hearing.

Google, Facebook, Yahoo and other Web giants launched a media blitz on Wednesday with full-page newspaper ads urging lawmakers to vote against the proposal. Vague language in the bill would force them to shut down the domain names of infringing sites and would lead to lawsuits, they said. Telecommunications firms, including Verizon Communications, complained that the bill would force them to stop Internet traffic that contained illegal content.

Supporters of the legislation, ranging from Hollywood studios to pharmaceutical companies, argued during the hearing that they are losing an estimated $135 billion a year in pirated material.

“Fundamentally, this is about jobs,” said Michael O’Leary, who represented the Motion Picture Association of America at the hearing. He argued that not just actors and directors are affected; piracy also has a ripple effect on thousands of businesses that are associated with the movie business.

Smith has said he hopes to move his legislation to markup before the end of the year. A similar Senate bill passed the Judiciary Committee in September.

The House proposal came about suddenly, critics say, and without consultation from high-tech and telecommunications firms.

“Inexplicably, and almost overnight, SOPA has morphed into a full-on assault against lawful U.S. Internet companies,” said Markham C. Erickson, executive director of NetCoalition, a group representing Web firms and public interest groups opposed to the law. “This makes no sense to us, nor will it to the millions of Internet users who depend on it for communications, commerce and democracy.”

A Verizon executive said in an interview Wednesday that the legislation puts too much of the burden on Internet service providers to create new technologies to monitor and stop illegal consumer use of Web content.

“We have a number of concerns with the bill,” said the executive, who spoke on the condition of anonymity because of the sensitive nature of the legislative push. “And we have been shut out of the process in writing this, even though it is very technical and requires us to use a range of technically difficult things to enforce this legislation.”

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