WASHINGTON (Reuters) - The U.S. Treasury Department named eight individuals and entities on Thursday as drug traffickers, including a Guatemalan drug lord believed to be one of the most prolific Central American narcotics traffickers, and banned Americans from having any dealings with them.

Treasury's Office of Foreign Assets Control said Guatemalan national Marllory Dadiana Chacon Rossell was the leader of a criminal operation with units in Honduras and Panama that supplied Mexican drug cartels, and connected her to seven other individuals and entities named as drug traffickers.

"Marllory Chacon's drug trafficking activities and her ties to the Mexican drug cartels make her a critical figure in the narcotics trade," said the office's director Adam Szubin.

Chacron Rossell is also under suspicion for laundering tens of millions of U.S. dollars in narcotics proceeds each month, which would make her the most active money launderer in Guatemala, according to Treasury.

One of the people named was Jorge Andres Fernandez Carbajal, Chacon Rossell's husband, a Honduran citizen that is accused of providing logistical support for his wife's operation.

OFAC worked with the Drug Enforcement Administration on the investigation and said its action was part of an ongoing effort under the Kingpin Act to apply financial measures against global drug trafficking organizations.

In addition to prohibiting Americans from conducting financial or commercial transactions with the designated traffickers, Treasury said that any of their assets that come under U.S. jurisdiction will be frozen.

(Reporting By Margaret Chadbourn)