U.S. military and CIA drones have flown through foreign skies to inflict remote-controlled attacks on terrorist targets, but, as part of a plan for immigration reform, their increased use to ensure border security at home has set off a heated controversy.

The plan presented last week by a bipartisan group in the Senate proposes boosting the number of drones patrolling the border with Mexico and using them to block the illegal trafficking of drugs, persons, arms and money.

The bill does not stipulate how many of these unmanned aircraft would be added to the fleet of 10 Predator drones currently operated by the Department of Homeland Security.

But the idea has its critics.

"I'm not clear about the cost/benefit ratio of these drones. They're very expensive and raise serious questions about protecting people's private lives," Jay Stanley, an analyst with the American Civil Liberties Union, told Efe.

States including Florida, Oregon, Virginia and Texas are weighing measures to regulate the use of drones for domestic law enforcement, Stanley said, and as he told Reuters, he doesn't want police "using them routinely on the general public, collecting biometric information on innocent people."

Criticism also comes from conservatives like David North of the Center for Immigration Studies, who has slammed the poor planning and financing of the DHS drones program.

A report by the DHS inspector general said the program launched in 2004 has shortcomings and lacks the budget it needs for the maintenance and repair of drones, which cost up to $20 million each.

Most Republicans in Congress insist that first of all the border must be secured before the eventual legalization and citizenship of the undocumented population can be considered.

President Barack Obama has begun pressuring for immigration reform and has said that, during his first term, the government achieved an almost 80-percent reduction in illegal entries compared with the year 2000. EFE