The United States has imposed sanctions against Syrian police unit and key Iranian security officials in connection with Syria's brutal crackdown on anti-government protesters.

The U.S. Treasury Department announced Wednesday it has targeted the Syrian Political Security Directorate – one of the country's four main security services – and the head of Syrian Air Force Intelligence, Major General Jamil Hassan, for human rights abuses.

Washington also designated the chief of Iran's Law Enforcement Forces, Ismail Ahmadi Moghadam, and his deputy, Ahmad-Reza Radan, for providing expertise to aid in the Syrian government crackdown. Radan in April allegedly traveled to Damascus, where he met with Syrian security officials.

The sanctions freeze any assets those designated may have in the U.S. and prohibit any dealings with them by American citizens or companies.

State Department spokesman Mark Toner said the sanctions have a broad reach because they limit the ability for other international companies to do business with the targeted entities.

Syria has been in turmoil for three months as pro-democracy forces press President Bashar al-Assad's government to reform.

Rights activists say at least 1,300 civilians have been killed since the uprising began in March. The Syrian government says hundreds of Syrian security forces also have died in violence it blames on terrorist groups.