He said the U.S. government will continue to push ICANN to adopt polices that are in the interest of the United States and an open Internet.

"Our announcement has led to some misunderstanding about our plan, with some individuals raising concern that the U.S. government is abandoning the Internet. Nothing could be further from the truth," Lawrence Strickling, the assistant Commerce secretary for communications and information, said in a statement . "This announcement in no way diminishes our commitment to preserving the Internet as an engine for economic growth and innovation."

The fears stem from the Commerce Department's announcement last Friday that it plans to give the Internet Corporation for Assigned Names and Numbers, an international nonprofit group, control over the technical system that allows computers to connect to Web addresses.

A top Commerce Department official pushed back Wednesday against concerns that the Obama administration is opening the door to an Internet takeover by Russia, China, and other authoritarian regimes.

The transition to full ICANN control of the Internet's address system won't happen until October 2015, and even then, there likely won't be any sudden changes. ICANN was already managing the system under a contract from the Commerce Department.

But having the ultimate authority over the domain-name system was the most important leverage the United States had in debates over the operation of the Internet. It was a trump card the U.S. could play if it wanted to veto an ICANN decision or fend off an international attack on Internet freedom.

Some have expressed concern that giving up that leverage could allow authoritarian governments or the United Nations to pressure ICANN to censor online content. For example, Rep. Marsha Blackburn, a Tennessee Republican, called the administration's announcement a "hostile step" against free speech.

"Giving up control of ICANN will allow countries like China and Russia that don't place the same value in freedom of speech to better define how the Internet looks and operates," she said in a statement on Monday.

The House Energy and Commerce Committee will hold a hearing on the plan next month and has promised "aggressive oversight." In a joint statement, Committee Chairman Fred Upton and Technology Subcommittee Chairman Greg Walden said that any changes to Internet governance should "be approached with a cautious and careful eye."

But Strickling noted that the National Telecommunications and Information Administration, a Commerce Department agency that he heads, will need to sign off on ICANN's proposal for managing the Internet address system.

"We have been clear throughout this process that any transition plan must meet the conditions of supporting the multistakeholder process and protecting the security, stability and resiliency of the Internet," Strickling said. "I have emphasized that we will not accept a proposal that replaces NTIA's role with a government-led or an intergovernmental solution. Until the community comes together on a proposal that meets these conditions, we will continue to perform our current stewardship role."

Strickling also pointed to supportive statements from Democrats including Senate Commerce Committee Chairman Jay Rockefeller and Rep. Anna Eshoo, as well as Republican Sens. Marco Rubio and John Thune. AT&T, Verizon, Cisco, Microsoft, and Google have also endorsed the move.

The U.S. government has long supported the "multistakeholder" model for Internet governance in which businesses, advocacy groups, and governments come together to make decisions. But because the Internet was invented in the United States, this country has historically had a central role in its management. As the Internet has grown, other countries have demanded a greater voice in decision-making. Edward Snowden's leaks about U.S. surveillance have only intensified the international pressure on the United States to relinquish its power.