Immigration rights advocates more than 500,000 strong marched in downtown Los Angeles, demanding that Congress abandon attempts to make helping illegal immigrants a crime and to build more walls along the border.
The massive demonstration, one of half dozen around the nation in recent days, came as President Bush prodded Republican congressional leaders to give some illegal immigrants a chance to work legally in the U.S. under certain conditions.
Saturday's march in Los Angeles was the largest in a series of demonstrations across the country. Police Cmdr. Louis Gray Jr. said aerial helicopters estimated the crowd.
Many marchers wore white shirts to symbolize peace and waved U.S. flags. Some carried the flags of Mexico and other countries, and wore them as capes.
Elger Aloy, 26, of Riverside, a premed student, pushed a stroller with his 8-month-old son at Saturday's Los Angeles march and called the legislation "inhumane."
"Everybody deserves the right to a better life," he said.
The U.S. House of Representatives has passed legislation that would make it a felony to be in the U.S. illegally, impose new penalties on employers who hire illegal immigrants and erect fences along one-third of the U.S.-Mexican border.
The Senate is to begin debating the proposals on Tuesday.
President Bush on Saturday called for legislation that does not force America to choose between being a welcoming society and a lawful one.
"America is a nation of immigrants, and we're also a nation of laws," Bush said in his weekly radio address about the emotional immigration issue that has driven a wedge into his party.
Bush sides with business leaders who want legislation to let some of the estimated 12 million undocumented immigrants stay in the country and work for a set period of time. Others, including Senate Majority Leader Bill Frist, say national security concerns should drive immigration reform.
"They say we are criminals. We are not criminals," said Salvador Hernandez, 43, of Los Angeles, a resident alien who came to the United States illegally from El Salvador 14 years ago and worked as truck driver, painter and day laborer.
Francisco Flores, 27, a wood flooring installer from Santa Clarita who is a former illegal immigrant, said, "We want to work legally, so we can pay our taxes and support the country, our country."
In Denver, police said over 50,000 people gathered downtown at Civic Center Park next to the Capitol to urge the state Senate to reject a resolution supporting a ballot issue that would deny many government services to illegal immigrants in Colorado.
Elsa Rodriguez, 30, a trained pilot who came to Colorado in 1999 from Mexico to look for work, said she just wants to be considered equal.
"We're like the ancestors who started this country, they came from other countries without documents, too," the Arvada resident. "They call us lazy and dirty, but we just want to come to work. If you see, we have families, too."
On Friday, tens of thousands of people were estimated to have joined in rallies in cities including Los Angeles, Phoenix and Atlanta and staged school walkouts, marches and work stoppages.