san luis, ariz. -- The federal government's border fencing effort has accelerated rapidly in recent weeks with barriers rising in towns from California to New Mexico and workers completing the longest stretch of continuous fencing on the U.S.-Mexico frontier.
The Department of Homeland Security reached its goal of completing 70 miles of new fencing by the end of this month, nearly doubling the length of barriers on the border to about 145 miles.
"When we make a commitment, we will carry through on the commitment," said Homeland Security Secretary Michael Chertoff, who went to Arizona on Friday to mark the progress and welded part of the fence in the town of Douglas.
Whether the new fencing slows illegal immigration remains to be seen, but the project is a milestone in another way. Once limited mainly to cities, fencing along the 1,952-mile border is now going up in rural areas, where much of the illegal immigration traffic has shifted in recent years.
Fleets of tractor-trailers loaded with fence posts and steel tubing have been crossing remote highways and deserts. Crews of National Guard troops spend hours welding raw materials under tarps. In some areas, contractors are installing the barriers at a pace of about half a mile per day.
A line of towering steel now slices for about 32 miles through a sea of sand from San Luis to the Tinajas Altas mountains. The fence, built to prevent incursions on the Barry M. Goldwater Range, is now the longest on the border, more than twice as long as the 14-mile fence separating San Diego from Tijuana.
"This is going to be a rude awakening for the crowds [of immigrants] that come in the fall," said Welby Redwine, a Boeing Co. engineer overseeing work in a canyon crisscrossed by smuggling trails in the Tinajas Altas mountains, 40 miles from the nearest town. "When they see it they're going to say, 'Wow, what happened?' "
In the vast Altar Valley, where hundreds of immigrants have died of dehydration over the years trying to reach Tucson 70 miles away, a 15-foot-high steel-tube fence is rising. Authorities hope the fence can slow the busiest illegal immigration corridor in the country, where more than 1 million people have crossed in recent years.
In Calexico, Calif., the same style of fencing will block a 7-mile stretch where smugglers have had easy access to launch boats across the All American Canal into California.
Other fencing has been built in the Arizona border towns of Naco and Douglas, and in Columbus, N.M.
And the government plans to break ground in coming months on new projects from California to Texas.
The progress marks an abrupt turnaround from one month ago, when the Homeland Security Department reported having completed only 15 of the 70 miles promised by Sept. 30, drawing criticism from many Republicans and activists against illegal immigration.
The Secure Fence Act, which President Bush signed into law last fall, called for 700 miles of new fencing. The administration set a goal of completing nearly 300 miles by the end of 2008.
The project got off to a slow start because of environmental assessments, land acquisition and fencing design that had to be completed before the start of construction, officials said.
The recent rapid pace of fence construction has been welcome news to federal border officials whose broader security plan -- called the Secure Border Initiative -- has experienced setbacks in recent weeks.
An Arizona project to line the border with camera towers as part of a high-tech "virtual fence" is behind schedule. Chertoff has suspended funding to project overseer Boeing Co. until progress is made.
New barriers have had an effect in San Luis, once one of the busiest crossing points in the nation. Immigrants by the hundreds would jump over the steel-mat fencing and disappear into nearby neighborhoods.
That route is now blocked by two new layers of fencing: a 15-foot-high steel-mesh secondary barrier and a chain-link fence topped with barbed wire.
The number of illegal immigrants apprehended daily in the area has dropped from 800 to as low as 15, according to Border Patrol officials.
Border experts say it is too soon to determine the overall success or failure of the effort, pointing out that previous fencing projects, most notably in San Diego, shifted immigrant traffic elsewhere.
U.S. Border Patrol Chief David V. Aguilar, in an interview in San Diego, said the plan to complete about 225 more miles of fencing next year would anticipate shifts in immigration patterns, much of it controlled by smuggling rings. "For the first time," Aguilar said, "we're getting ahead of where the criminal organizations are going to go."