The centre of Manchester's Chinatown has been sealed off after knife-wielding gangs clashed on its streets and six men were stabbed.
Up to 20 men from the city's Chinese community were involved in a series of fights, police said.
The injured have been treated in hospital following the attacks on George Street at 0220 BST.
A 32-year-old man is in a critical condition, two others have serious injuries and three have lesser wounds.
Ch Insp Chris Hill sought to reassure the community: "These attacks are indeed gang-related, it's not a random attack on members of the public.
"They are safe to walk through Manchester as well as the Chinatown area of Manchester."
George Street has been cordoned off while forensics carry out their investigations.
Patrols have been stepped up in the area and a mobile police station has been set up.
Officers who can speak Mandarin and Cantonese are also on hand, police said.
Ch Supt Caroline Ball, of Greater Manchester Police, said: "The community of Chinatown has been left understandably shocked by this incident.
"The police are highly visible in the area to address peoples' concerns."
She appealed to anyone with any information to contact police.