Mexicans who have passed security checks will be allowed to visit the United States for up to 30 days instead of the current three-day limit, government officials said Monday.

The change, long sought by Mexicans and border-state politicians, is a gesture that could help President Bush win support in the election battleground states of Arizona and New Mexico.

The 30-day limit will be available to Mexicans who hold so-called laser visas, which require background checks and other security measures, Sen. John Cornyn (search), R-Texas, confirmed Monday.

The Homeland Security Department declined comment.

It was not immediately clear when the change would take effect. There will be no change to a separate rule that restricts Mexicans to traveling no more than 25 miles from the border.

Asa Hutchinson, the Homeland Security undersecretary who oversees border and transportation security, planned a briefing Tuesday on immigration issues.

Politicians and businesses from states along the border with Mexico have pushed for longer stays for Mexicans as post-Sept. 11 security has tightened. The tougher enforcement has hurt border economies, officials say.

They've also argued the United States discriminates against its southern neighbor because Canadians are allowed to enter the country for up to six months on little more than proof of citizenship and can travel throughout the United States.

"Mexicans visiting with laser visas invest in our real estate, travel and support local industry," Cornyn said. "They have shown they are willing to visit this country legally and should be allowed to stay as long as Canadians engaged in similar travel and commerce. It's the right thing to do for both our border economy and our short-term, nonimmigrant visitors."

The senator began pushing for equity for Mexican visitors last November and has been negotiating with the Homeland Security Department for the extended stay. He called 30 days a "good start and a much more reasonable time limit." But he said Mexican visitors, who undergo far more scrutiny, should get the same freedom Canadian visitors enjoy to travel in the United States.

"Specifically, the 72-hour limit should be extended to six months to accommodate the realities of trade, tourism and commerce along the border," he said.

Other government officials outlined the plan but would not comment for the record before it was released.

Mexicans with laser visas regularly make quick trips across the border to shop, visit friends and relatives, travel, vacation or do business. The visas are obtained through American consulates and embassies. Mexicans undergo criminal background checks (search) to get the card, which is embedded with the holder's digital fingerprints and photo.

The United States shares a nearly 2,000-mile border with Mexico. Texas, New Mexico, Arizona and California share a border with Mexico.

New Mexico is one of 11 states where President Bush and Democratic presidential nominee John Kerry are running even and could go either way in the November election. Kerry campaigned in Arizona on Monday, and Bush and Kerry were to follow on Wednesday, evidence of the candidates intense struggle for the state's 10 electoral votes.