U.S. sanctions targeting Syria and Iran have inadvertently undermined the opposition movements they are intended to help, making it more difficult for those groups to access technologies that can evade electronic surveillance and censorship, according to security experts and activists.

The economic sanctions imposed by the Obama administration have forced many Western companies, including technology firms, to sever relationships with Syria and Iran. The measures have helped to isolate those governments internationally.

But many of the same measures also have blocked access to online services and software — including e-mail, blogging platforms and security tools that prevent user activity from being traced — that could be helpful to opposition movements, experts say.

“We are fighting on two sides: the side of the regime and the side of the sanctions,” said Dlshad Othman, a Syrian activist who works with opposition groups across the region.

The concern most frequently raised by activists and U.S.-based nonprofits that support them is the difficulty of getting anti-tracking software, which usually is free of charge, into the hands of those on the ground. Othman said U.S. sanctions have made it much harder and more time-consuming to get anti-surveillance tools installed on activists’ phones and computers.

“And sometimes we’re not successful,” he added. “So people take risks, and they are filming and uploading pictures without protection, so the regime can easily arrest them or even kill them.”

The Obama administration has granted exemptions from trade restrictions with Syria and Iran to allow U.S. tech firms to make their goods and services available to customers in those countries. But the sheer complexity of the sanctions — and the steep fines for violating them — have in many cases kept U.S. firms from seeking clarification or attempting to obtain export licenses.

Even when sanctions are relaxed, problems can persist. In 2011, for instance, the Treasury Department granted an exemption allowing Google and others to offer free Web-browsing software in Iran, but the same exemption was made for Syria only this summer.

“The thing about the sanction effort is that . . . they’ve actually done more harm than good,” said Jillian C. York of the Electronic Frontier Foundation, a rights group that was among the signatories to an open letter this summer that called on large Internet companies to apply for export licenses.

Concerns about the unintended consequences of the sanctions have prompted the administration to review current policy in Syria, officials said Tuesday. Among the possible changes: a presidential order clarifying what software and services could be provided to the country.

A long, complex process

U.S. officials said they have already issued general licenses to allow the export of “free, mass-market personal communications software and services” to Syria and Iran. They have also issued specific guidance on what is permitted and what is not.

Companies, officials note, have been given the opportunity to apply for licences that would exempt them from sanctions.

“We’ve done a lot to encourage companies to apply for these licenses,” said a Treasury Department official, speaking on the condition of anonymity because he was not authorized to talk on the record. “If they aren’t doing so, that may be more of a business decision on their part.”

But those familiar with the process required to obtain special export licenses say it is complex and can take several months in some cases.

A spokeswoman for Google, which restricts access to some of its services in Syria and Iran, said the company is doing what it can within the current laws.

“As a U.S. company, we remain committed to full compliance with U.S. export controls and sanctions,” said the spokeswoman, Christine Chen. “We remain equally committed to continue exploring how we can help more people around the globe use technology to communicate, find and create information.”

For the Obama administration, part of the challenge has been to craft sanctions that undermine authoritarian regimes without affecting ordinary citizens. That has been particularly difficult in the case of the technology sector. Communications equipment, for instance, is crucial for opposition movements, but cellphones also provide the Syrian and Iranian governments with tracking information that allows them to monitor and find dissidents.

“This isn’t sophisticated surveillance equipment, it’s basic [telecom] equipment — and so as a result, people who say the mobile phone is the dictator’s best friend aren’t entirely wrong,” said Katrin Verclas, a co-founder of the global activism organization MobileActive.org. “They are perfect tracking devices just by their very core function and the way that they work.”

Members of the opposition, activists say, are well aware of the surveillance on cellphones and Web browsers, but they either do not know how to evade it or don’t have the tools to do so.

‘It doesn’t make any sense’

In its efforts to support Internet freedom, the Obama administration has provided funding to companies and nonprofit groups that make certain tools available. But activists say some of those organizations also have been affected by recent sanctions.

“It doesn’t make any sense for all of us to get money to produce all of these tools, for them then not to be able to go into the hands of people who can use them,” Verclas said.

Syria and Iran have the capability to censor certain online content, and both countries have laws requiring telecommunications companies operating within their borders to hand over information on customers to government agents on demand.

They have also become proficient at using the Internet to uncover members of the opposition. In Syria, a pro-government group calling itself the Syrian Electronic Army has advertised fake Facebook and Skype software, for instance, that is embedded with spyware.

“Syrian dissidents know that they are under persistent attack by pro-government electronic actors . . . but they don’t always have a very good idea of what measures to take to protect themselves,” said John Scott-Railton, a researcher who has worked on anti-censorship initiatives in the Middle East. “Reducing this vulnerability is partly an issue of making them aware of the right tools and partly about making it easier to access these tools.”

In the meantime, activists said, members of the opposition continue to take online risks.

The irony of the situation, they added, is that as members of the opposition struggle to access new technologies, the Iranian and Syrian governments have been able to circumvent sanctions through a network of suppliers.

“The governments have money, they have means, there are regimes that support the Syrian regime, so they can get equipment,” said Othman, the Syrian activist. “It’s very easy for them. But we are paying the price.”

Tom Hamburger contributed to this report.