Even as Syrians lost access to the Internet on Thursday, people outside the country could still browse the Syrian government's many Web sites for much of the day because they are hosted in foreign countries, including the United States.
By nightfall, after being contacted by The New York Times, several host companies said they were taking down those sites. They and similar companies had been identified in reports published by Citizen Lab, a research laboratory that monitors North American Web service providers that host Syrian Web sites.
For example, the Web site of SANA, the Syrian state news agency, is hosted by a Dallas company, SoftLayer Technologies. It is one of a handful of Internet providers based in the United States that sell their services, often unknowingly, to Web sites operated by the government of President Bashar al-Assad.
HostDime.com in Orlando, Fla., hosts the Web site of Syria's Ministry of Religious Affairs. Jumpline.com hosts the site of the country's General Authority for Development. The government of Hama, a city that has seen heavy clashes between rebels and government troops, operated its Web site through WeHostWebSites.com in Denver.
An executive order by President Obama prohibits American companies from providing Web hosting and other services to Syria without obtaining a license from the Treasury Department.
On Thursday, State Department officials confirmed that providing the services was a violation of the United States sanctions. "Our policies are designed to assist ordinary citizens who are exercising their fundamental freedoms of expression, assembly and association," a spokesman, Mark C. Toner, said.
A SoftLayer spokesman, Andre Fuochi, would not comment about the SANA Web site, but in a statement he said the company "rigorously" enforces "prevailing laws and regulations and acts swiftly and vigorously if we find our users to be in violation."
Dennis Henry, the vice president of operations at HostDime.com, said he had been unaware of the Syrian government Web site, but that it was hosted by a customer's server housed in HostDime.com's data center.
"We have contacted our direct client whose server is housing the Web site to express our concerns," Mr. Henry said. On Friday, Mr. Henry said the company had removed the Web site.
Mike Griffin, an owner of Handy Networks, a wholesale Web service and the owner of WeHostWebSites.com, said he too had been unaware of the Syrian government Web site but had asked that it be removed.
"We comply with all U.S. sanctions, including those prohibiting the exportation of Web hosting services to Syria," he said.
Upon being told of the Syrian Web site, Jumpline's chief operating officer, Andy Mentges, said in an e-mail that it would be "shut down within the hour."
The Internet shutdown across Syria on Thursday underscored how the 20-month conflict, which has left more than 40,000 people dead, has increasingly moved to the Web. Both sides use cyberattacks to advance their causes.
The hosting of government Web sites overseas represents a growing technological sophistication by the Assad government. "Look what they did with chemical weapons. They can do the same with communications," said Robert B. Baer, a former C.I.A. operative based in the Middle East. "When the Syrians want to do something, they can do it."
It is also likely that Syrian rebel and jihadi groups host Web sites inside the United States. The Syrian government appears to be aware that its Web sites are safer and easier to control when operated on servers inside the country.
In July, the Assad government ordered that all official Web sites be hosted inside Syria. But in case of an emergency or an Internet shutdown like the one on Thursday, the government also maintains Web sites based in the United States, Canada and Britain, said Helmi Noman, a senior researcher at Citizen Lab.
"This most recent Internet disruption in Syria highlights the issue of Web hosting and how the regime is able to make use of servers outside Syria to promote its message while locally hosted sites are down," Mr. Noman said.world
This article originally appeared in The New York Times.