Barack Obama hosted a summit on government surveillance and digital privacy attended by Apple chief executive Tim Cook, Google vice-president Vint Cerf and the boss of US telecoms network AT&T on Thursday.

The US president attended in person, sources told the Politico blog, as did other technology company executives. Additional attendees included representatives of the Center for Democracy and Technology and Gigi Sohn, leader of internet campaign group Public Knowledge.

The meeting was apparently prompted by growing concerns among US technology companies that revelations from the Guardian and others about the extent and depth of surveillance by the National Security Agency, and the companies' obligation to allow access to data under secret court rules, could be damaging their reputation and commercial interests abroad.

The gathering followed a closed-doors meeting earlier this week with Obama's chief of staff Denis McDonough and general counsel Kathy Ruemmler at the White House.

On the agenda at Tuesday's meeting were the surveillance activities of the NSA, commercial privacy issues and the online tracking of consumers.

"This is one of a number of discussions the administration is having with experts and stakeholders in response to the president's directive to have a national dialogue about how to best protect privacy in a digital era, including how to respect privacy while defending our national security," one official told Politico.

McDonough and Ruemmler met members of the Information Technology Industry Council, TechNet and Tech America, which represent a range of companies from defence contractors to digital giants Facebook, Google and Microsoft.

Campaigners including the American Civil Liberties Union and the Electronic Privacy information Center were also present, Politico's Tony Romm reported.

The Guardian's revelations about the breadth of the NSA's access to data, particularly relating to foreign individuals, has created PR problems for US companies. Apple has set its sights on China as a huge potential growth market, but if people there fear eavesdropping by the US government it could harm sales. And Google stands to lose business in cloud computing to European rivals if customers fear similar eavesdropping. Cloud computing companies have estimated they could lose billions of dollars of business as a result.

The White House is also battling to respond to growing unrest over surveillance of citizens by the state and the vast caches of data many digital giants are now storing about individual consumers.

Obama has promised more public debate about the country's counterterrorism activities and privacy safeguards in general amid signs of widespread support for NSA whistleblower Edward Snowden, but officials have so far declined to provide details about this week's technology summits.

The meetings came as a wave of Americans posted messages of support to the former security contractor, whose leaks exposed the extent of government sponsored surveillance in the US and Europe.

A website launched by the digital rights group Fight for the Future on Wednesday has attracted more than 10,000 posts expressing support for Snowden's actions. Billed as an exercise to put faces to statistics, the website features a combination of photographs of individuals holding up signs and written words of support.

In June, Reuters/Ipsos found 31% of respondents believed Snowden was a patriot, while 23% thought he was a traitor. Another 46% said they did not know. Gallup found in June that 53% of respondents disapproved of government snooping programmes, while just 37% approved and 10% had no opinion.

In a statement, Fight for the Future cofounder Tiffiniy Cheng said: "We've seen an unbelievable response already – the messages keep streaming in. The government reads the same polls that we do. They know that Snowden has the public's support. But now we're adding faces to those statistics. As someone who volunteered and worked for Obama's election, I feel totally burned by the president's civil liberties and human rights records. If he truly cares about representing the American people, he should turn his attention to shutting down the NSA's illegal surveillance programs, and leave Mr Snowden alone."

The website was launched shortly before Obama pulled out of a presidential meeting with Russia's leader Vladimir Putin in Moscow next month. This followed Russia's decision to grant Snowden asylum.