The Senate will take up immigration legislation early next year that will go beyond improved border security to the contentious issue of including illegal immigrants in a guest worker program, Senate Majority Leader Bill Frist (search) said Tuesday.

Frist, R-Tenn., said he wants to address the enforcement of workplace laws concerning immigrants and the status of as many as 12 million people who are in the U.S. illegally. He intends to deal with these issues in a border security bill.

Frist appeared with Sens. John McCain (search), R-Ariz., and John Cornyn (search), R-Texas, who have championed opposing approaches on the issue of illegal aliens and guest worker programs.

McCain, with Sen. Edward Kennedy (search), D-Mass., backs legislation that would allow illegal aliens to work in the U.S. for up to six years. After that, they either must leave or be in the pipeline for a green card, which denotes lawful permanent residency.

Cornyn and Sen. Jon Kyl, R-Ariz., support a proposal that would require undocumented workers to return to their home country to apply for a temporary worker program.

McCain said there was about 90 percent agreement on immigration issues. The remaining 10 percent "is huge," he said, but "the American people want this to happen."

President Bush (search) has urged Congress to act on a guest worker program and has proposed a plan that would allow undocumented workers to get three-year work visas. They could extend that for an additional three years, but would then have to return to their home countries for a year to apply for a new work permit.

"The president is vital to this," McCain said. "He understands the issue better than anyone else" because of his experiences as governor of Texas.

GOP leaders in the House have indicated support for a more piecemeal approach, taking up border security first and putting off for later the tougher issue of how to organize a guest worker program.

Border security was a priority in the 2006 Homeland Security spending bill that the president recently signed into law. It included money to hire 1,000 new Border Patrol agents, 2,300 beds for detention and custody operations, 250 criminal investigators, 100 Immigration and Customs Enforcement agents and additional unmanned aerial vehicles.

Also Tuesday, Sen. Chuck Hagel (search), R-Neb., introduced bills dealing with national security, employment security, temporary workers and illegal aliens.

Hagel agreed that border security must be dealt with up front because "the American people won't accept immigration reform until they are convinced we are controlling our borders."

Hagel would allow undocumented workers to gain legal status if they pass national security and criminal background checks, have lived in the U.S. for at least five years, have paid taxes, have demonstrated knowledge of English and pay a fine of $2,000.

Those who fail to meet work or residence requirements would be required to return to their home country to apply for a visa.