A one-day nation-wide strike and business boycott gathered steam on Monday to demand legal rights for millions of illegal immigrants, with many US businesses shutting down voluntarily to avoid disruption.
Early reports suggested many of the estimated 11.5-12 million illegal immigrants in the country were staying away from work, despite a mixed message from immigrant-rights organisations, some of which opposed the action.
In New York City's Union Square, the normally bustling open-air market operated at a fraction of its typical activity. Cheap, immigrant-run buses services from New Jersey to the city were not running.
Demonstrators formed "human chains" at several points around the city. Hundreds, including school children, lined up in Queens, stretching for three blocks on both sides of the street waving US and Latin American flags and banners saying, "We are Americans" and "Full Rights for All Immigrants."
"Everyone's an immigrant here.
The only real American is the Indian," said Puerto Rican-born Rene Ochart, a doorman at the posh Hotel Pierre in Manhattan's Upper East Side, who was working as usual.
A bill passed by the House of Representatives in December that would make all illegal immigrants into felons provoked a mass protest movement, bringing people who previously worked and lived in the shadows of US society into the streets.
Across the country, several major meat-packing plants were closed but operators had tried to prepare for the shutdown by stepping up production over the weekend.
Fast food company McDonald's Corp said some of its restaurants were operating for shorter hours or drive-thru service only. The National Association of Chain Restaurants said the boycott could hurt its members.
"Unfortunately, these work boycotts have the potential to handcuff the very businesses that have worked so hard for immigration reform," said association spokesman Scott Vinson.
Police in Los Angeles were bracing for two massive marches, with hundreds of thousands of people expected to heed a call from Mayor Antonio Villaraigosa, Roman Catholic Cardinal Roger Mahony and others to make their voices heard.
Police in Chicago were also expecting up to half a million people to march, while smaller rallies were planned in most major cities across the nation.
Wage and labour expert Oren Levin-Waldman of the Metropolitan College of New York said the main impact would be to inconvenience people but a one-day protest would have little economic effect despite the major role played by immigrants in the economy.
"The real issue with respect to the immigrant work stoppage is that the country relies on illegal immigrant workers to keep prices down," he said.
Recent polls suggest a majority of Americans would support legislation being debated in the Senate that would allow many illegal immigrants to join a legal guest worker program and later apply for citizenship. An NBC/Wall Street Journal survey last week found 68 percent would support this with 28 percent in opposition.
However, the same poll found that only 17 percent of Americans thought the day-long boycott and strike would help the immigrants' cause, while 57 percent said it would harm it.
The walkout caused a dispute over strategy within the ranks of immigrant-rights advocates for precisely that reason, with some fearing the action would trigger a backlash.
Yet proponents say the move was needed to prod US President George W. Bush and a divided Congress to end an election-year squabble and enact legislation.
Illegal immigrants, who flood across the Mexican border at a rate of half a million a year, work mostly at low-paid jobs in agriculture, construction, restaurants, as janitors, meat packers, maids and gardeners and many other occupations.
A recent study by the American Farm Bureau Federation said a crackdown on illegal immigrant labour could cause production losses in US agriculture of $5 billion to $9 billion in the first one to three years and up to $12 billion over four or more years.
Passing immigration reform has been difficult because the Republican Party is badly split on the issue between those who support giving illegal immigrants a path to citizenship and hard-liners who want to focus on beefing up border security and punishing companies who employ illegal immigrants.
The House passed a get-tough bill last December that would reclassify illegal immigrants as felons, punish those who help them and build a fence along much of the US-Mexican border.
Chicago teacher Francisco Palomo, 46, said he had skipped work to protest against the House bill, which could penalise anyone who extended help to an illegal immigrant.
"I don't want to be criminalised. If I help out some guys, if I give some lodging, that's a felony?" he said.