The White House says it is part of an effort designed to prevent the countries from using information technology to repress domestic dissent.
US targets Syria and Iran technology firms in new sanctions
The White House said this was part of an effort designed to prevent the countries from using information technology to repress domestic dissent.
The sanctions announced yesterday prohibit Americans from doing business with the organisations and individuals listed, and freeze their US assets.
They target Syria's and Iran's intelligence and security services as well as telecommunications companies SyriaTel, which controls 55 per cent of Syria's mobile network. It is owned by Rami Makhlouf, a first cousin of Bashar Al Assad, the Syrian president.
Also targeted was Datak Telecom, one of the largest internet service providers in Iran.
Among the measures the White House announced was a provision to sanction individual members of the regimes in Syria and Iran who "commit or facilitate grave human-rights abuses via information technology".
The only individual mentioned was Ali Mamluk, the head of the Syrian General Intelligence Directorate.
Six of the seven entities listed were already under sanctions. The only addition was Datak Telecom.
Nevertheless, the White House described the sanctions in a statement as "novel" and said they "degrade the ability of the Syrian and Iranian governments to acquire and utilise such technology to oppress their people".
The sanctions will also "strengthen international norms against using information and communications technology to commit human rights abuses", the statement said.
The sanctions come after Barack Obama, the US president, issued an executive order that allows the US to impose sanctions on foreign nationals who have used advanced technology to commit human rights abuses.
They were part of a package of measures the White House said was designed to better predict and prevent atrocities around the world, including the creation of an Atrocities Prevention Board.
Its mission would be to identify where there are risks of mass killings and mass atrocities and respond with a "range of steps" including diplomatic, economic and military options, according to a White House statement.
The board was to meet for the first time yesterday afternoon.
Mr Obama announced the measures in a speech at Washington's Holocaust Museum, where he was visiting to mark Holocaust Remembrance Day.
Preventing mass atrocities and genocide was not only a US national security interest, it was a "core moral responsibility", Mr Obama said.
In his speech, he also singled out what he called the "unspeakable violence" in Syria, and he outlined steps the administration was looking to take to increase the pressure on Damascus.
"The Syrian people have not given up, which is why we cannot give up," the US president said while announcing the new sanctions, which he described as "one more step that we can take toward the day that we know will come - the end of the Assad regime that has brutalised the Syrian people".