Social media tools that allowed democracy campaigners to organize rallies across the Middle East and North Africa are being monitored by Tehran and Damascus to "facilitate serious human rights abuses," an administration official said.
Obama was to unveil the executive order, which he signed on Sunday, in a speech at the U.S. Holocaust Memorial Museum.
The order freezes U.S. assets linked to people found to have aided satellite, computer and phone network monitoring in Syria, where more than 9,000 people have been killed in more than a year in turmoil, as well as Iran, where Washington believes authorities are clamping down on opposition groups.
The order cites the Syrian General Intelligence Directorate, the Syrian cell phone company Syriatel, Iran's Ministry of Intelligence and Security, Iran's Islamic Revolutionary Guard Corps, Iran's Law Enforcement Forces and the Iranian Internet provider Datak Telecom, as well as a number of individuals.
"The United States condemns the continuing campaigns of violence and human rights abuses against the people of Syria and Iran by their governments and provides a tool to hold accountable those who assist in or enable such abuses through the use of information and communications technology," it read.
The sanctions coincide with reports from Iran on Monday that the country's main oil export terminal had been hit by a suspected cyber attack affecting the Oil Ministry and national oil company.
The Washington Post reported that Obama would also offer grants to companies to develop alerting tools to make activists aware of dangers of crackdowns or mass killings.
The president's response to the yearlong violence in Syria as well as Iran's steps towards nuclear development has been sharply criticized by Republicans during this election year.
Obama, a Democrat, has been emphasizing the potential for a diplomatic resolution to the crises while trying to add pressure on both governments through financial and other sanctions. He was elected in 2008 in large part due to his promise to wind down U.S. military engagement overseas in Iraq and Afghanistan.