The California nonprofit organization that operates the Internet's levers has always been a target for such global heavies as Russia and China that prefer the United Nations to be in charge of the Web. But these days, the Internet Corporation for Assigned Names and Numbers is fending off attacks from a seemingly unlikely source: the Obama administration.

Concerned about the growing movement to cede oversight to the U.N., the U.S. government, which helped create ICANN in 1998, has been reprimanding the nonprofit group to give foreign nations more say over the Web's operations.

The battle has come at a sensitive time for ICANN, which this month is meeting with foreign governments as it pulls off the biggest expansion ever of Web suffixes - including .gay, .muslim and .nazi. Also this fall, the nonprofit organization is seeking to hold on to its federal contract to oversee the Web's master database of addresses - a sweeping power that governments fear could be used to shut down foreign domains that the United States finds unsavory.

"There's a deeper question of how the world is reacting to a small company - even a nonprofit - completely in charge of a key part of the Internet. Is that acceptable? There's no 100 percent comfortable solution here," said Steve Crocker, ICANN's vice chairman, who lives in Bethesda and is the chief executive of Shinkuro, a technology company.

With some Middle East countries shutting down the Internet within their borders to curb uprisings, the question of who runs the Web is increasingly figuring into global foreign policy debates. Some fear that governments such as those of Libya or Iran could more easily crush rebellions if they gained more control over the Internet's inner workings.

ICANN quietly wields vast influence over the Web, a power unfamiliar to many Americans and elected officials. Based in an off-campus University of Southern California building, the company has more than 100 employees and is led by a chief executive and a board of directors comprised of private sector executives and technology experts. ICANN's core function: Decide which Web addresses get seen on the Internet.

In Washington, ICANN remains somewhat mysterious to elected officials, according to Nao Matsukata, a senior policy adviser to the Coalition Against Domain Name Abuse, a grass-roots organization in Washington. Matsukata's main problem, he said, is trying to explain what ICANN is to people on Capitol Hill. His group has met with more than 50 members of Congress.

"Sometimes, when we're in meetings on the Hill, they're just nodding their heads," said Matsukata, a former trade official in the George W. Bush administration. "Very few people understand where all these decisions are coming from and that this is something that impacts us every day of our lives. Someone is determining what is allowed, what is not allowed, and someone is profiting from these things."

The tiny nonprofit group can be especially provocative for a trade press that covers its every move, and for a rival U.N. agency, the International Telecommunications Union. When the ITU, a 145-year-old agency of nearly 200 nations and territories, held its annual meeting in October in Mexico, a Syrian emissary representing Arab states raged against ICANN as if it were an enemy nation.

"Do not surrender to the ICANN!" Nabil Kisrawi yelled during one of the conference's sessions, according to a story in the Register, an online publication on Internet governance. "There is even a representative of the ICANN in this room!" Kisrawi said. (Kisrawi recently died.)

Other nations have been mobilizing against ICANN. China, which monitors dissident activity on the Web, has been leading a campaign among dozens of developing nations to lobby the U.N. for oversight over ICANN, according to former and current ICANN officials. And a coalition of former Soviet states led by a Russian minister has been pushing the U.N. to obtain veto power over ICANN.

Some countries also worry that the new wave of Web suffixes might be too controversial and that others might require companies to spend vast sums to protect their online brands and trademarks. (Who gets .merck? The U.S. drug company? Or the German drug company with the same name?)