WASHINGTON - (AP) -- The Bush administration, trying to topple drug kingpins, moved Friday to block the financial assets of two leaders of the violent
  North Valle drug cartel in Colombia that has smuggled tons of cocaine into the United States.

  The Treasury Department's Office of Foreign Assets Control added Diego Leon Montoya Sanchez and Luis Hernando Gómez Bustamante to the U.S.
  government's list of specially designated narcotics traffickers.

  The action means that any assets belonging to the two men found in the United States or in its jurisdiction will be frozen and Americans are forbidden
  from doing business with them.

  Treasury officials hoped this decision would further expose, isolate and incapacitate Colombian drug cartels and their agents.

  The drug kingpins named Friday ''smuggle . . tons quantities of cocaine into the United States,'' officials said.

  In addition, Treasury added 21 people and 13 businesses in Colombia it believes are acting as fronts for leaders of the cartel.

  Treasury officials said it would take some time to determine if any of the individuals and businesses added to the list Friday had assets in the United
  States.

  A 1995 executive order gives the Treasury Department the authority to try to financially paralyze suspected drug cartels and kingpins targeted by the
  United States.

  With the addition of Friday's names, the U.S. government has ordered the assets belonging to 613 individuals and businesses blocked, Treasury officials
  said.

  That list includes 12 kingpins from Colombia's drug cartels, including Cali cartel leaders, officials said.