WASHINGTON -- The United States on Thursday slapped fresh sanctions on the Hezbollah leadership, accusing the Shiite militant group that dominates the Lebanese government of supporting Syrian President Bashar al-Assad in his fight against the opposition forces.

Hasan Nasrallah, Hezbollah's secretary general, and Mustafa Badr Al-Din and Talal Hamiyah, the group's alleged "senior terrorist leaders," were targeted by the Department of Treasury respectively for providing support to al-Assad and backing the organization's terrorist activities in the Middle East and around the world.

"By aiding al-Assad's violent campaign against the Syrian people and working to support a regime that will inevitably fall, Hezbollah's ongoing activity undermines regional stability and poses a direct threat to Lebanon's security," said David Cohen, under secretary of Treasury for terrorism and financial intelligence.

"Hezbollah's actions, overseen by Hasan Nasrallah and executed by Mustafa Badr Al-Din and Talal Hamiyah, clearly reveal its true nature as a terrorist and criminal organization," he said in a statement.

Washington branded Hezbollah as a specially designated global terrorist in October 2001, and has imposed rounds of sanctions against it over the years, while Nasrallah was blacklisted in January 1995.

The Treasury first imposed sanctions against Hezbollah over its support for the Syrian government last month, accusing the group of providing "training, advice and extensive logistical support" to al-Assad's government, which has been trying to fend off an 18- month uprising involving foreign forces.

Arguing for its latest move, the agency stated that Hezbollah has played "an increasingly active role" in recent months in supporting the Syrian government and "further enabling the regime to carry out its bloody campaign against the Syrian people."

Washington and its allies are seeking al-Assad's ouster for a political transition in his country.