FRANKFURT, Germany — On the global Internet these days, the United States is less trusted and more alone. The worldwide network was born on U.S. shores, but that matters little to the growing number of nations now demanding shared control.

An escalating feud over Internet governance is threatening to transform a U.N. summit in Tunisia next week into an acrimonious showdown between the United States and challengers including the European Union.

The debate is over whether Washington, through its oversight of a quasi-independent agency, should continue as the ultimate administrator of all the Web's domains — not only over ".com" but also the country-specific ones like ".cn" for China.

At its essence, the struggle is over an information superstructure that is already the main conduit of world commerce. It is also about free speech and information control. The arbiters of Internet policy could profoundly shape international relations in coming years.

"I am torn about this, as I suspect many Internet law experts are. On the one hand, basic principles of international law suggest that a common carrier essential to commerce in all nations should be internationally controlled," said Frank Pasquale, a professor at Seton Hall Law School in Newark, N.J.

"On the other hand," Pasquale added, "many of the countries most eager to impose international control also have bad records on free speech issues, political prisoners."

The so-called World Summit on the Information Society was originally conceived to address the digital divide — the gap between information haves and have-nots — by raising both consciousness and funds for projects.

Instead, it has centered largely around Internet governance: oversight of the main computers that control traffic on the Internet by acting as its master directories so Web browsers and e-mail programs can find other computers.

Although the U.S. government has largely delegated management to a private organization with international board members, the Internet Corporation for Assigned Names and Numbers, or ICANN, it has ultimate veto power over all decisions.

Washington set a course for confrontation when it declared over the summer that it will retain such oversight indefinitely, despite what many countries thought was a longstanding policy to one day completely turn the function over to ICANN.

The EU responded in September by insisting that some sort of new combination of governments and the private sector share the responsibility of policing the Internet. Before, the push for an international takeover of ICANN mostly came from such developing countries as Brazil, South Africa and China.

The reasons for resentment of U.S. control are numerous, beginning with objections to Bush administration foreign policy.