U.S. lawmakers have approved a measure to double the number of U.S. troops in Colombia to 800.

The government of Colombian President Alvaro Uribe welcomed the support in its fight against the drug trade and left-wing Marxist rebels. But human rights groups criticized the increase, saying more U.S. troops could escalate the violence in the South American country.

The U.S. Congress also voted to increase the number of American civilian contractors in Colombia from 400 to 600.

The United States is providing $1.3 billion for "Plan Colombia," an initiative launched by Colombia's government to fight the illegal drug trade, protect human rights, and expand economic development.