In an unusual joint statement, leading Internet companies called Monday for new legal restrictions on government spy programs that the companies view as an increasing threat both to their customers' privacy and their own business interests.

"The U.S. government should take this opportunity to lead this reform effort and make things right," Facebook CEO Mark Zuckerberg said in a statement that accompanied an open letter to the president and Congress. The letter was also endorsed by top executives at Apple (AAPL), Google (GOOG) and other Internet giants who are usually fierce competitors.

"Recent revelations about government surveillance activities have shaken the trust of our users," said Yahoo (YHOO) CEO Marissa Mayer.

Many of the companies have been beefing up their own technological defenses, including using advanced forms of encryption, since news leaks about the National Security Agency's collection of Internet users' data emerged over the summer. They've also waged individual public relations efforts to convince consumers that companies don't hand over files unless faced with legal orders from government agencies.

But after reports that the NSA sought to neutralize encryption and also tapped into some companies' overseas data links, the tech industry has now launched a coordinated campaign to convince federal policy makers that spy agencies must be reined in.

Along with halting "bulk data collection" of Internet communications, the companies called for enacting "sensible limitations" on the government's authority to demand specific user files. They also asked for more checks and balances, including independent court oversight, of surveillance programs.

NSA officials said they focus on individuals overseas, but news reports and documents leaked by ex-NSA contractor Edward Snowden indicate the agency gathered bulk "metadata" and Internet traffic between large numbers of people, including Americans, who are indirectly associated with primary targets of investigation.

Tech leaders outlined their recommendations in an open letter and website -- reformgovernmentsurveillance.com -- endorsed by AOL, Apple, Facebook, Google, Linkedin, Microsoft, Twitter and Yahoo.

Leaders at those companies are often courted by politicians for their tech savvy, "hipness" factor and deep financial pockets. Now they hope to exert their influence in Washington, where President Barack Obama has said he will outline his ideas on potential surveillance reforms in coming days. Several companies have already voiced support for congressional bills that would enact some of the changes proposed Monday.

While the website doesn't offer many details, Internet advocates said it represents a major escalation in the industry's response to the controversy. "The company reform principles go far beyond earlier calls for transparency," said Leslie Harris of the Center for Democracy and Technology. She called it "a game changer."

But some critics said the companies are late to the fight.

"A big part of the problem is that the companies decided to collect all that data," said Marc Rotenberg of the Electronic Privacy Information Center. "We've been pushing them from the start to develop better practices to safeguard users' privacy. That means collecting less personal data, deleting it when it's no longer needed and putting in place protections like encryption. Typically the companies have been slow to do that.''

Industry spokesmen argue that the companies' use of data for commercial purposes, such as delivering targeted advertising, is different from government surveillance, since customers can opt out of commercial data gathering or decide not to use those services.

Tech companies also said they respect the government's role in defending against terrorism and other threats. "We understand that governments have a duty to protect their citizens," the letter said.

Executives were careful not to blame only the United States for abuses. Google CEO Larry Page said his company invested heavily in encryption to protect user information and added: "This is undermined by the apparent wholesale collection of data, in secret and without independent oversight, by many governments around the world. It's time for reform and we urge the U.S. government to lead the way."

Industry groups are concerned that some countries such as Brazil have reacted to the NSA leaks by considering laws that would require Internet companies to store their citizens' data within their national borders. Experts say that such requirements, in addition to being costly, could vastly disrupt the Internet's ability to efficiently route data anywhere in the world.

Analysts have estimated the industry could lose billions of dollars if consumers and businesses decide they can't trust U.S. companies with sensitive data.

"People won't use technology they don't trust. Governments have put this trust at risk, and governments need to help restore it," said Brad Smith, general counsel at Microsoft.

Contact Brandon Bailey at 408-920-5022. Follow him at Twitter.com/BrandonBailey.