Demonstrations are being held in up to 100 cities and towns including Chicago, Los Angeles, Las Vegas and New York.

Rally organisers described the protest movement as "the fight for civil rights of our generation".

Unions, civil rights groups, schools and churches want Congress to approve a provision allowing undocumented workers to remain in the country.

President George W Bush backs a guest-worker scheme but faces stiff opposition within his Republican party.

On Friday, the US Senate failed to reach agreement on a compromise deal that would allow some 11.5 million illegal immigrants to apply for US citizenship.

It will resume the debate on the issue in two weeks' time, after the spring recess.

Other demonstrations were also held in New Mexico, Minnesota, Michigan, Alabama, Utah, Oregon, Idaho and California.

BBC