US Immigration and Customs Enforcement officers have rounded up more than 200 people for violating immigration laws during a five-day sweep in the Los Angeles area, which sparked a protest on Thursday.

In addition to arresting 212 undocumented immigrants, federal agents also served more than 100 notices to local businesses that they will be audited to determine whether they are employing people who are in the country illegally.

The raids triggered a demonstration by a small group of immigration advocates chanting 'stop the deportations' who blocked a Homeland Security van from entering the federal Metropolitan Detention Center.

LA raids: US Immigration and Customs Enforcement officers arrested 212 undocumented immigrants during a five-day operation in the Los Angeles area (pictured)

The ICE raids sparked a protest on Thursday, in which immigration advocates blocked a Homeland Security van from entering the federal Metropolitan Detention Center

Police were called in and issued a dispersal order but no one was arrested.

A statement from the agency said that 88 per cent of the 212 people arrested in the sweep were convicted criminals. The remaining 12 per cent were non-criminals.

More than half had prior felony convictions for serious or violent offenses, such as child sex crimes, weapons charges, and assault, or had past convictions for significant or multiple misdemeanors.

'Because sanctuary jurisdictions like Los Angeles prevent ICE from arresting criminal aliens in the secure confines of a jail, our officers are forced to conduct at-large arrests in the community, putting officers, the general public and the aliens at greater risk and increasing the incidents of collateral arrests,' said ICE Deputy Director Thomas Homan.

Protesters block an Homeland Security van from moving near the intersection of Alameda and Aliso in Los Angeles on Thursday night

A single protester argues with LAPD officers, who were called to the scene to disperse the crowd in downtown LA on Thursday)

P{olice issued a dispersal order but no one among the protesters was arrested

Gov. Jerry Brown, a Democrat, signed in October a bill declaring California a 'sanctuary state.'

Some will be prosecuted for illegal entry or re-entry into the US and others will be administratively processed for deportation, immediately removed or held for immigration court hearings.

During the operation, Homeland Security Investigations agents served notices on 122 businesses that they will be audited to determine if they are employing people who are in the country illegally. The audits can lead to civil fines or criminal prosecutions.

Similar audit notices were recently given to 77 Northern California businesses and about 100 7-Eleven stores in 17 states and the District of Columbia.

Last year, ICE carried out 1,360 audits and made 139 criminal arrests and 172 administrative arrests. Businesses were ordered to pay $97.6million in judicial forfeiture, fines and restitution and $7.8million in civil fines, including one company whose financial penalties totalling $95million represented the largest payment ever levied in an immigration case.