But Mr. Bush again pressed Congress to change immigration laws to allow illegal immigrants already in the U.S. to work here.
"If you have people coming here to do jobs Americans aren't doing, we need to figure out ways they can do so in a legal basis for a temporary period of time," he said in a speech at the U.S. Border Patrol station in Yuma.
Mr. Bush said illegal immigrants should not be given amnesty and would have to pay a fine and meet other criteria before they could apply for U.S. citizenship.
The president hoped to send a message — particularly to conservative critics from his own party — that the stepped-up border enforcement is working. His get-tough message was meant to prod Congress into passing a guest worker program for immigrants, a signature domestic policy goal.
Mr. Bush was joined by Sen. Jon Kyl, R-Ariz., whose support is seen as critical to any deal in the Congress.
Another lawmaker vital to Mr. Bush's effort, Democratic Sen. Edward Kennedy of Massachusetts, said Monday: "President Bush did the right thing today by speaking out."
"Only a bipartisan bill will become law," Kennedy added. "There is a lot of common ground, especially in the need to strengthen our borders and enforce our laws, though important differences remain to be resolved."
Senate Majority Leader Harry Reid, D-Nev., has scheduled time for immigration debate in May.
Both the president and the Democratic-run Congress are eager to show some accomplishment on a core issue like immigration. But it's a sticky subject, and the fault lines don't necessarily fall along party lines. For Mr. Bush, opportunities to see through his domestic agenda are shrinking.
Administration officials led by Homeland Security Secretary Michael Chertoff and Commerce Secretary Carlos Gutierrez have been meeting privately for weeks with Republican senators. That expanded to a meeting in late March with key senators from both parties.
Out of that session, a work-in-progress plan emerged — one described as a draft White House plan by officials in both parties and advocacy groups who got copies of the detailed blueprint.
The White House disputes that characterization. Spokesman Scott Stanzel said it was only a starting point, an emerging consensus of Republican senators and the White House.
Regardless, the floated proposal has already met opposition. Thousands of people marched through Los Angeles on Saturday, spurred in part by what they called a betrayal by Bush.
The plan would grant work visas to undocumented immigrants but require them to return home and pay hefty fines to become legal U.S. residents. They could apply for three-year work visas, dubbed "Z" visas, which would be renewable indefinitely but cost $3,500 each time.
Stressing security, Mr. Bush said, "If you don't man your border and don't protect your borders, people are going to sneak in.
"You cannot fully secure the border until you take pressure off the border," the president said. "And that requires a temporary worker program."
He also pushed his plan to let illegal residents become citizens, provided they pay fines, take steps to become well-rounded Americans and get behind others who have been waiting.
It is impractical to try to round up and send home 11 million to 12 million illegal immigrants, he said. "It may sound good," he said. "It won't happen."
Arriving in Yuma, Mr. Bush and Chertoff took a quick look at the "Predator," an unmanned plane that border officials use to monitor the region.
Mr. Bush pointed to two new layers of fencing that have been erected at the border since he visited the same spot a year ago.
"It's amazing the progress that's been made," he told border officials. "I was most impressed by your strategy, but more impressed by the fact that it's now being implemented."
With up to 12 million illegal immigrants in the U.S., lawmakers haven't agreed on how to uphold the law without disrupting lives, eroding the work force and risking political upheaval.
Mr. Bush is hopeful for a legislative compromise by August.
The president's relations with Congress these days have been soured by the war in Iraq. He is at odds with Democratic lawmakers over a bill to extend war funding in Iraq and Afghanistan.