Border Patrol agents are stepping up surprise inspections on domestic trains, buses and ferries, nabbing illegal immigrants far from the border.

In Vermont, Washington, Louisiana, New York and elsewhere, the agents, who have the authority to search any mode of transportation within 100 miles of the border, are working routes that don't cross into Canada or Mexico. Most checks are at bus and train stations and ferry terminals.

"The first line of defense is on the immediate border," says Joe Giuliano, deputy chief in the patrol's Blaine, Wash., sector, which includes Alaska and Oregon. "We have to have a second line of defense."

In February, agents began checking passengers taking the ferry between Washington's San Juan Islands and the terminal in Anacortes, Wash. So far, Giuliano says, they have caught 59 illegal immigrants, two with criminal records, and eight U.S. citizens, most on drug violations.

The patrol started ferry checks after hiring more agents, he says. "To be honest, it's something we should have done for a long time," he says. "We were so short on resources."

Immigrant and civil liberties advocates argue that the agents focus more on certain passengers based on skin color and accent.

"They will see a white person and ask, Where were you born?' Then they will see a person of color and ask, Do you have ID?' " says Caroline Kim with the Detainment Task Force in Syracuse, which provides bail for some detained immigrants and helps them through the legal process.

The Border Patrol says it does not engage in racial profiling.

Giuliano believes the inspections deter illegal immigrants and may be scaring off potential terrorists. "They never know when we're going to show up and what form we're going to take," he says.

In the agency's Buffalo sector, which has about 400 miles of border, agents had arrested 1,786 illegal immigrants through transportation checks by the end of August, 11 months into the fiscal year, compared with 1,299 in all of last year, spokesman A.J. Price says.

Agents in the New Orleans sector, which covers seven states, have arrested 1,754 illegal immigrants on buses through Sept. 18. That's a 32 percent increase overall of the last fiscal year, says assistant chief Ronny Kastner.