WASHINGTON--The Homeland Security Department is considering the use of unmanned aircraft to track drug smugglers, illegal immigrants and terrorists along the porous U.S. border with Mexico, a top official told a Senate panel Tuesday.

"There's a lot of interest in this," Robert Bonner, commissioner of the Bureau of Customs and Border Protection, told the homeland security subcommittee. "I think there's potential there."

With no human on board, Predators and other remote-controlled aircraft can watch over a potential target for 24 hours or more and fly for hundreds of miles. They can carry cameras, sensors, communications equipment or missiles.

Homeland Security Secretary Tom Ridge endorsed the use of drones last month before members of the Senate Commerce, Science and Transportation Committee.

"We need to equip (Border Patrol agents) with this kind of technology if our expectations legitimately are for them to combat terrorism," Ridge said.

Support is growing for unmanned aircraft since their success during the conflicts in Iraq and Afghanistan.

Spy cameras aboard a drone allowed U.S. commanders to watch the capture of Palestinian hijacking suspect Abu Abbas and oversee the rescue of Army prisoner-of-war Pfc. Jessica Lynch. On another day, they foiled an Iraqi ambush on U.S. and British troops. In November, an unmanned Predator drone killed suspected al-Qaida operatives in Yemen.

The Senate Armed Services Committee last week approved a big jump in the 2004 defense budget for unmanned systems, including land-based and underwater systems. The committee approved $135 million more than the White House proposed, which was 25 percent higher than last year's appropriation.

Armed Services Committee chairman John Warner, R-Va., wrote a letter to President Bush on April 9 saying that unmanned aircraft could monitor long stretches of border, nuclear power plants, pipelines and dams. They could also be used to augment Coast Guard patrols of the U.S. coastline.

"I believe that the potential applications for this technology in the area of homeland defense are quite compelling," wrote Warner.

Jay Stanley, spokesman for the American Civil Liberties Union, cautioned that aerial surveillance is limited now by the cost and difficulty of flying a plane over a target. The use of drones could significantly expand the amount of surveillance on Americans, he said.

"It definitely evokes the most paranoid visions of Big Brother's eye in the sky," Stanley said.

William Shumann, Federal Aviation Administration spokesman, said drones flying along the border wouldn't interfere with commercial flights if they flew low enough. He said interest in the aircraft is growing for civilian use as well as among law enforcement and the military.

Separately, congressional investigators told a House Judiciary subcommittee Tuesday that they were able to easily get inside America's borders with falsified driver's licenses and birth certificates made with off-the-shelf software and home computers.

The false documents were not challenged once by border officials when they tried to get in from Mexico, Jamaica, Barbados or Canada, said Robert Cramer, the director of special investigations for the General Accounting Office. Sometimes, he said, the agents were not even asked for identification.

"The results of our work indicate that Bureau of Customs and Border Protection inspectors are not readily capable of detecting counterfeit identification documents and that people who enter the United States are not always asked to present identification," Cramer said. "This does provide an opportunity for individuals to enter the country illegally."