Tea party groups converged on a remote section of the U.S.-Mexico border on Sunday to show support for Arizona's controversial immigration law and hear from more than a dozen conservative speakers, many of them candidates running for office in crowded Republican primaries.

Several speaking to the crowd of more than 400 demanded Congress and President Barack Obama devote more resources to increase border security in remote areas like the site of Sunday's demonstration southeast of Tucson.

"We are going to force them to do it, because if they don't, we will not stop screaming," said former state Sen. Pam Gorman, one of 10 Republicans vying for an open congressional seat in north Phoenix. Gorman carried a handgun in a holster slung over her shoulder as she mingled with demonstrators.

Obama on Friday signed a bill directing $600 million more to securing the U.S.-Mexico border — money that will pay for hiring 1,000 more Border Patrol agents along with customs agents, communications equipment and expanded use of unmanned aerial vehicles.