Seeking to exploit the Internet’s potential for prying open closed societies, the Obama administration will permit technology companies to export online services like instant messaging, chat and photo sharing to Iran, Cuba and Sudan, a senior administration official said Sunday.

On Monday, he said, the Treasury Department will issue a general license for the export of free personal Internet services and software geared toward the populations in all three countries, allowing Microsoft, Yahoo and other providers to get around strict export restrictions.

The companies had resisted offering such services for fear of violating existing sanctions. But there have been growing calls in Congress and elsewhere to lift the restrictions, particularly after the postelection protests in Iran illustrated the power of Internet-based services like Facebook and Twitter.

“The more people have access to a range of Internet technology and services, the harder it’s going to be for the Iranian government to clamp down on their speech and free expression,” said the official, who spoke on condition of anonymity because the announcement had not been made yet.

The decision, which had been expected, underscores the complexity of dealing with politically repressive governments in the digital age: even as the Obama administration is opening up trade in Internet services to Iran, it is shaping harsh new sanctions that would crack down on Iranian access to financing and technology that could help Iran’s nuclear and missile programs.

Critics have said these sanctions are leaky and ineffective, and some say it makes more sense to spread digital technology, which makes it harder for governments to restrict the flow of information within societies, and to prevent their people from contact with the outside world.

The Treasury Department’s action follows a recommendation by the State Department in mid-December that the Office of Foreign Assets Control, which is run by the Treasury, authorize the downloading of “free mass-market software” in Iran by Microsoft, Google and other companies.