The Commerce Department is investigating whether technology produced by a California company helped Syrian police monitor dissidents amid a bloody crackdown there, U.S. officials said Thursday.

Commerce officials are attempting to determine whether Blue Coat Systems of Sunnyvale, Calif., had prior knowledge that its equipment and software was being used by the Syrian government, according to several U.S. officials. They spoke on the condition of anonymity to describe an ongoing investigation.

Calls and e-mails to Blue Coat officials seeking comment on Thursday were not returned.

The company has previously said it did not sell equipment or software to the Syrian government, but it has acknowledged that its products are being used there and could have been obtained through a third party. U.S. sanctions prohibit sales of most goods to the nation; investigators are attempting to determine who provided the Blue Coat technology to Syria.

A statement from the company this month said: “Blue Coat is mindful of the violence in Syria and is saddened by the human suffering and loss of human life that may be the result of actions by a repressive regime. We don’t want our products to be used by the government of Syria or any other country embargoed by the United States.”

The Blue Coat technology is not intended for surveillance purposes, according to the company, but it has functions that could help authorities monitor electronic communications while also blocking people from accessing certain Web sites and some forms of social media.

On Thursday, three senators urged the Obama administration to investigate whether Blue Coat and another California-based company had provided “tools of repression” to Damascus.

“The sale of U.S.-made equipment that may have contributed to ongoing violence is unacceptable and should be investigated as soon as possible,” said the letter from Sens. Mark Kirk (R-Ill.), Robert P. Casey Jr. (D-Pa.) and Christopher A. Coons (D-Del.).

The Commerce Department has primary responsibility for controlling surveillance exports. Eugene Cottilli, spokesman for the Commerce Bureau of Industry and Security, declined to comment.

“We do not discuss any matters related to ongoing investigations,” Cottilli said.

Should the Commerce Department find that Blue Coat knowingly violated licensing rules, it could fine the company up to $1 million, according to Daniel Minutillo, a lawyer based in Silicon Valley who specializes in export law and technology. Smaller civil penalties and other actions also are possible.

Blue Coat last month hired law firm McDermott Will & Emery to lobby for the company after news reports about the use of its technology in Syria, according to disclosure forms.

Syrian President Bashar al­-Assad has been battling an uprising that began during the Arab Spring and has grown increasingly violent in recent months. The United Nations estimates that 3,500 people have been killed since protests began. This week, the Arab League suspended Syria for failing to honor a peace deal that included a pledge to halt attacks on protesters.

Recent news reports have revealed that authoritarian governments have used U.S. and other Western technology to monitor dissidents and other citizens. In some cases, middlemen have facilitated the transfer of this technology.

U.S. companies that wish to export devices that are “primarily useful for the surreptitious interception of wire, oral or electronic communications” must apply to the Commerce Department for a license, according to the export administration regulations.

Sales by U.S. companies to Syria are illegal under sanctions imposed by President George W. Bush in 2004. When selling items to countries under U.S. sanctions, a license is required to override the restrictions.

At a congressional hearing Nov. 9, Assistant Secretary of State Jeffrey Feltman said the Blue Coat technology being used in Syria had not been granted any export licenses.

The senators who asked the Obama administration to investigate Blue Coat also asked for an investigation into the California-based company NetApp.

Bloomberg News has reported that NetApp equipment is part of a Syrian Internet surveillance project designed to intercept and catalogue all e-mail in Syria.

“We absolutely do not support the sale of NetApp equipment to Syria,” chief executive Tom Georgens said in a statement Thursday. “We have no interest in providing product to a banned country, and I just wanted to make sure that was clear.”

Staff writer Julie Tate contributed to this report.