London (CNN) Hundreds of restaurant workers in London's Chinatown downed their kitchen knives Tuesday for a five-hour strike over what they say are heavy-handed immigration raids specifically targeting their community.

The unprecedented strike in a community that is better known for keeping a low profile is the latest manifestation in Britain of growing concern about some aspects of UK immigration law.

Around 100 restaurants closed their shutters and a crowd of more than 500 people gathered for the protest before marching to the Home Office in Westminster.

#Solidarity with all those protesting in London's #Chinatown this afternoon to say no to racist immigration raids #JusticeforChinatown #StopRacistRaids pic.twitter.com/NgaOIpF5XQ — Stand Up To Racism (@AntiRacismDay) July 24, 2018

"We are striking to demonstrate the frustration and anger of the community towards the increasing and unfair immigration raids on a growing number of restaurants," said Joseph Wu, chief executive of the London Chinatown Chinese Association.

The Home Office would not comment on Tuesday's protests, but told CNN in a statement that immigration enforcement officers had visited businesses in Chinatown on seven occasions in the first six months of this year. On five of those visits, they encountered offenders -- 19 people in total.

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