WASHINGTON — The United States hit Iran's intelligence ministry with sanctions Thursday, claiming it had supported Syria's crackdown on dissidents, fueled repression at home and aided Al-Qaeda.

The US Treasury Department said Iran's Ministry of Intelligence and Security supported the Syrian regime as it "continues to commit human rights abuses" and played a "central role" in repression in Iran.

The sanctions mean any property owned by the ministry in the United States or under US control will be seized. Ministry officials will be banned from travel to the US.

While the sanctions are likely to have little material impact, the move represents another gear shift in Washington's opposition to the alleged Iranian role in Syria's year-long crackdown.

The US has long said that weapons and advice was flowing between the Middle Eastern allies.

In 2011 President Barack Obama listed Iran's Revolutionary Guards in an executive order linked to human rights abuses in Syria. The Treasury Department had previously placed sanctions on the Iranian national police for being involved in the crackdown.

In January senior US officials told AFP that Iran had been supplying munitions to aid the suppression, an initiative spearheaded by the head of Tehran's elite Revolutionary Guards.

Thursday's new sanctions will only inflame tensions between Washington and Tehran further.

In recent months a long-running dispute over Iran's nuclear program and its alleged support for Hezbollah has been augmented with tit-for-tat threats of sanctions and a series of attacks around the globe which some say Iran perpetrated.

They include a plot to assassinate Saudi Arabia's ambassador in Washington, Iranian threats to close the Strait of Hormuz -- a vital oil shipping route -- and a series of bombings in India, Georgia and Thailand.

"Today we have designated the (intelligence ministry) for abusing the basic human rights of Iranian citizens and exporting its vicious practices to support the Syrian regime's abhorrent crackdown on its own population," Treasury sanctions chief David Cohen said in a statement.

"In addition, we are designating the (ministry) for its support to terrorist groups, including Al Qaida, Al Qaida in Iraq, Hezbollah and Hamas, again exposing the extent of Iran's sponsorship of terrorism as a matter of Iranian state policy."