The Obama administration accused two Lebanese financial institutions Tuesday of laundering millions of dollars in drug-smuggling money to support the militant group Hezbollah, with some of the cash being routed through U.S. banks.

Treasury Department officials linked the Lebanese institutions to what they said is a criminal network that raises cash through sales of narcotics and used cars and other enterprises spanning four continents. The money from the operations, some of which allegedly went to Hezbollah, was funneled to Lebanon to be laundered through legitimate banks and private businesses, the officials said.

The United States and many of its allies regard Hezbollah as a terrorist group. In Lebanon, where the group is based, it holds seats in parliament and operates numerous social development programs.

U.S. officials formally designated Lebanon-based Halawi Exchange Co. and Kassem Rmeiti and Co. as institutions supporting a criminal enterprise and took steps to block their access to the U.S. banking system. It was the latest in a series of U.S actions targeting Hezbollah, which has long been linked to sales of narcotics and other contraband to raise money for its political and military wings in southern Lebanon.

David S. Cohen, undersecretary for terrorism and financial intelligence at the Treasury Department, said Hezbollah’s overseas enterprises produce huge profits that then must be laundered through legitimate businesses.

“Hezbollah, like any other criminal enterprise, wants to convert cash into usable funds that can be transferred through the formal financial system,” Cohen told reporters at a news conference in Washington.

The money “moves internationally, and a good portion of it comes to banks here in the United States,” he said.

Efforts to reach the two companies by e-mail and phone were unsuccessful.

The move comes two years after the Obama administration initiated similar measures against the now-defunct Lebanese Canadian Bank for allegedly providing money-laundering services to the Ayman Joumaa narcotics network, which also has been linked by U.S. officials to Hezbollah.

The United States and several other governments have linked Hezbollah to attacks on primarily Israeli and Jewish targets in the Middle East and around the world. In recent years, Hezbollah’s political wing has emerged as one of the key players in Lebanon’s government. The group receives funding and weapons from Iran and has supplied fighters and equipment to bolster Syrian President Bashar al-Assad’s government in its battle against rebels.