The United States is urging Syria to open up its markets to U.S. companies' computers and software, but fears over piracy and Internet access restrictions are holding back American technology companies from investing there.

Senior executives of five big U.S. technology companies including Microsoft Corp and Dell Inc expressed their concerns to Syrian President Bashar al-Assad during a five-day trip last week, two members of the delegation told Reuters.

The trade mission was led by Secretary of State Hillary Clinton's top technology adviser, Alec Ross, and Jared Cohen, a member of her Policy Planning Staff.

U.S. tech companies expect Syria's population to double in the next seven years and they want to tap into the youth to promote U.S. businesses and Washington's human rights agenda.

The talks last week represent a new stage in U.S. diplomatic efforts in which the issue of Internet censorship is increasingly placed on the agenda during direct talks with other governments.

U.S. tech companies are carefully watching moves by the State Department, especially after Google Inc in March announced that it was going to move its China servers to Hong Kong following the high profile diplomatic spat with Beijing over censorship.

Senior executives from Cisco Systems Inc , VeriSign

Inc and Symantec Corp also traveled with the delegation in a trip that included meetings with academics, students and small- and medium-size businesses.

One delegation member said that during the trip they tried to clear up a misperception in Syria that U.S. companies can't invest there because of U.S. sanctions against trade and investment.

They told officials in Damascus that exemptions for some technology granted in 2004 under former President George W. Bush allow for companies to sell their products to Syria as long as those tools are not used against the Syrian people, the delegation member said.

You can sell Dell computers, you can sell Microsoft Office, you can sell Cisco routers, but despite that waiver that is not happening, the delegation member told Reuters on Wednesday on the condition of anonymity.

The companies told Syrian officials that they are worried about the lack of enforcement to combat piracy and intellectual property theft, and widespread corruption, another member said.

They also sought assurances by the government that the technology will not be used against Syria's general population, they said, adding that Syrian officials pledged to adopt some laws aimed at improving the environment for tech investments this year.

Sheldon Himelfarb, an expert on technology and diplomacy at the U.S. Institute of Peace, said U.S. officials need to become smarter about relationships between sanctions and the impact on citizen activists in closed societies.

We need more trips like this, Himelfarb said.

The mission to Syria was unique because it was a high-level engagement during a strained relationship between the two countries. Their ties, however, have improved since U.S. President Barack Obama took office.

Syria has emerged from a five-year diplomatic isolation, with the United States and European Union seeking closer ties with Damascus and pushing for a resumption of peace talks between Syria and Israel.

The trip also follows an issue of waivers by Washington in March to allow U.S. technology companies to export chat and social media software to Iran, Sudan and Cuba, with the hope the move will help their citizens communicate with the outside world.

The Internet was an important communication channel for Iranian protesters disputing election results last year.

If the next generation of Syrians are able to get access to these tools of technology, then they're going to have connections to the outside world, another delegation member said.

(Editing by Gerald E. McCormick)