US Secretary of State Antony Blinken (Photo by AFP)
The Treasury Department announced that it was taking action against seven people including Qatari nationals Ali al-Banai and Ali Lari, who it said have secretly sent tens of millions of dollars to the Iranian-backed Lebanese militant group.
Secretary of State Antony Blinken said that Hezbollah uses "global networks of financiers and front companies to support its malign activity" and praised the cooperation of Qatar.
"This represents one of the most significant joint actions we have taken with a Gulf Cooperation Council partner to date and underscores our extensive bilateral cooperation on countering terrorism finance," Blinken said in a statement.
Nearby Bahrain also took action by freezing the bank accounts of al-Banai's nephew on the island and will prosecute three people, the Treasury Department said.
Bahrain has tense relations with Iran but Qatar has comparatively friendly ties as it seeks to maintain dialogue around the region.
Qatar has frequently come under criticism for not doing more to prevent fund-raising for extremist groups on its soil but the concerns more frequently involve Sunni Muslim militants such as Al-Qaeda and the Taliban.
Qatar's relationship with the United States shot up in August as it became the transit point for more than half of the 100,000 people evacuated from Afghanistan as the Taliban took control.
Hezbollah, which the United States and several other Western nations consider a terrorist group, is a political powerhouse in Lebanon with the Shiite Muslim movement recently bringing in Iranian fuel to ease an acute shortage.