The House author of a border security bill that triggered massive street protests stood firm Friday against amnesty for illegal immigrants and predicted tough negotiations with the Senate on compromise legislation.

The Senate passed its sweeping bill 62-36 Thursday after two weeks of debate and difficult votes that tested the strength of a coalition of bipartisan senators who supported the opportunity for U.S. citizenship that their bill would give most of the estimated 11 million to 12 million people who are in this country illegally.

"This will set up a very difficult House-Senate conference committee because the approaches taken by the House and Senate on this issue have been 180 degrees apart," said Rep. James Sensenbrenner, chairman of the Judiciary Committee and principal author of the more stringent House bill.

"Amnesty is wrong," he told a news conference.

President Bush said Thursday that the House "began a national dialogue" when it passed an immigration bill last year and he said he "looked forward to working together" with lawmakers to produce a bill he could sign.

He declined to answer a question later about whether he thought the House and Senate could succeed in finding a compromise for their disparate positions on the issue.

But he did say that an effective measure would protect U.S. borders, make employers responsible for people they hire, create a temporary worker program, deal with the illegal immigrants already in the U.S. and "honor America's great tradition of the melting pot."

Soon after passing their bill, senators challenged the House to move away from its enforcement-only prescription and toward something more in line with what Bush wants.

Sen. Dick Durbin, D-Ill., said he hoped the House would see the legislation as a rare opportunity. "We should seize this moment so America can move forward," he said.

Sen. Patrick Leahy described the Senate bill as a start. but said getting a final agreement "is still a 50-50 proposition."

Yet House Majority Leader John Boehner said House negotiators will oppose "troubling policies that encourage open borders and invite more illegal immigrants into our country."

"Our most important priority is to secure our borders and stop illegal immigration," said Boehner, R-Ohio.

GOP Rep. Peter King of New York, chairman of the House Homeland Security Committee, said he would vote against any legislation that included amnesty or legalization for illegal immigrants. King is expected to be among the House negotiators.

Senate Majority Leader Bill Frist, R-Tenn., who voted for the Senate bill, said he would seek to have negotiations begin soon.

Republican Rep. Jeff Flake of Arizona, who sponsored an early version of the Senate bill in the House, urged House Speaker Dennis Hastert to follow Frist's lead "so we can begin the difficult task of reaching a consensus."

Sen. Lindsey Graham, R-S.C. argued for finishing the bill before the November elections.

"This is one problem that is not going to wait until the next election," Graham said. "If you win or lose because you make a hard decision, so be it."

Politics has been an undercurrent as the Senate has tried to write legislation that would satisfy unions, immigration hawks, businesses and advocates for Latinos, and other interests. Several leaders involved in the debate, including Frist and Sen. John McCain, R-Ariz., are considering 2008 presidential runs.

Latinos are the fastest growing segment of the electorate. Thousands, including some illegal immigrants, joined street protests to denounce the House bill and call for broader legislation.

"The Latino community and the rest of the country want effective immigration reform that brings order and fairness to our system," said Janet Murguia, National Council of La Raza president.

Senate leaders agreed that their success in conference will depend greatly on Bush.

"Now the time has come for very active participation by the president," said Sen. Arlen Specter, R-Pa. "I believe the president will put a very heavy shoulder to the wheel."

A chief architect of the Senate bill, Edward M. Kennedy, D-Mass., said he would "welcome the strong leadership of the president of the United States in this undertaking."

The House bill, which passed on a largely party-line vote last year, is generally limited to border enforcement. It would make all illegal immigrants subject to felony charges. It has no provision for either a new temporary worker program or citizenship for men, women and children unlawfully in the country.

The Senate bill, in contrast, would mark the most far-reaching changes in two decades by:

— Urging the hiring of 1,000 more Border Patrol agents this year and 14,000 by 2011.

— Endorsing Bush's plan for a short-term deployment of National Guard troops to states along the border with Mexico.

— Calling for the construction of 370 miles of fencing on the border.

The guest worker program would admit 200,000 individuals a year. They eventually could apply for a green card, which confers legal permanent residency.

A separate program envisions admission of an estimated 1.5 million immigrant farm workers who also may apply for permanent residency

For illegal immigrants, those in the country for five years could stay, keep working and eventually apply for citizenship. They would have to pay at least $3,250 in fines and fees, settle back taxes and learn English.

Illegal immigrants in the country for more than two years but less than five would have to travel to a point of entry before re-entering the United States legally and beginning the lengthy process of seeking citizenship.

An immigrant in the country illegally for less than two years would be required to leave with no guarantee of return.