OAKLAND, Calif. -- Waving American flags, thousands of people marched for immigrant rights in California on Monday, taking part in a wave of demonstrations across the nation.

Huge throngs gathered in Sacramento, San Jose, Fresno and Oakland, while small groups turned out in San Diego and in Santa Ana, the Orange County seat. Demonstrators gathered for an evening rally in Los Angeles, where the movement was energized by a March 25 rally that unexpectedly drew hundreds of thousands.

Marchers chanted and waved U.S. and Mexican flags in Sacramento, where organizers estimated the crowd at 5,000 but the California Highway Patrol unit in charge of Capitol protection would not provide an official estimate.

"Our roots are Mexican and we don't want to lose that, but at the same time I feel more American," said Fausto Cervantes of Galt, who said he found work picking crops after coming to the U.S. illegally.

At one point, marchers halted to drown out John Boker of Dixon, who yelled, "USA, USA, no to amnesty."

Boker, 52, a carpenter, said he was not against immigration, just illegal immigration.

"You come to a country, you should follow the law of the land," Boker said.

The protests, latest in a series that began last month, seek to help an estimated 11 million immigrants who are illegally in the United States by influencing decision-making in Washington, D.C.

A bill passed by the House would crack down on illegal immigrants and strengthen the U.S. border with Mexico. A broader overhaul of immigration law stalled in the Senate last week and lawmakers went on a two-week break.

"I think it was wrong for them to leave Washington and not have an agreement to have a guest worker program and to make sure we secure the borders," Gov. Arnold Schwarzenegger said after touring the state's flood operations center in Sacramento on Monday.

Like other marches, the San Jose demonstration was a sea of American flags in contrast to some previous protests that were heavy on Mexican and other nations' flags and raised concerns about the message being sent.

"We love our country, we love Americans," said marcher Mary Vasquez, 45, a pastry chef from San Francisco.

"We need the freedom for everybody no matter what color or race," said Balbir Singh Dhilan, also among several thousand walking in San Jose. "We are the same Americans that other people are."

Oakland protesters were estimated to number more than 2,000.

"We are united. We are not going anywhere," they chanted as they marched nearly nine miles to a federal building.

"A lot of us here broke the law to get here," said Umberto Rosas, 36, as he carried his 1-year-old daughter, Sandy, on his shoulders. "That doesn't mean we don't love America."

Police estimated about 5,000 people marched in Fresno, although march organizer Polo Chavez said volunteers counting people as they walked by put the crowd at more than 10,000.

The predominantly Hispanic protesters marched a Catholic Church to City Hall.

"The concept that undocumented workers cause this country more harm than good is ridiculous," said Vincent Lavery, 70, of Fresno. An immigrant from Ireland, Lavery said he carried his homeland's flag along with a U.S. flag to symbolize it wasn't just a Hispanic issue, but a human rights issue.

In Santa Ana, which is about 76 percent Hispanic, several hundred people marched around the federal courthouse waving American flags. Police put the crowd at about 300 people, said Sgt. Theron Reed.

Many chanted, "Si, se puede (Yes, we can)," and carried signs that read "Legalization not deportation" and "Somos America (We are America)."

Adriana Lopez, 27, attended the rally with her two young daughters. Lopez, who immigrated illegally from Mexico 11 years ago, said she was at first afraid to attend the rally but decided it was too important to miss.

"It's important to support because we are family, and we work hard to have a better life. My two girls were born here, and we don't want to be separated," she said.

Demonstrator Jose Perez, 55, said he was the son of immigrants and became a U.S. citizen after serving in the Vietnam War in 1971.

"As citizens of this country, our parents were immigrants. And this country is founded on the principle of opening its doors to everyone," said Perez, a registered Republican. "We're taking note of who is really listening to the voices of their constituents, and there will be a change. Today we march, and tomorrow we vote."

American flags outnumbered Mexican flags at the rally, where vendors were selling U.S. flags for $2 each.

About 50 people gathered in San Diego, where on Sunday there had been a march by 50,000 people.

The group met in a park to place 464 wooden crosses on the ground in memory of Mexicans who have perished trying to cross the border into the United States.

"There should not be any more people dying to cross this border," said Enrique Morones, director of Border Angels, the group that organized the event at Chicano Park in the Hispanic Barrio Logan neighborhood.

"It's important to remember the people who came across and never made it," said Robert Fambrini, pastor at Our Lady of Guadalupe Church, who blessed the crosses. "The border -- the frontera -- is still a matter of life and death."