According to US media sources, police in California are reacting to a gunshot that has injured many persons.
After 22:00 local time on Saturday, the event took place in Monterey Park, which is located about eight miles (13 km) east of Los Angeles (06:00 GMT on Sunday).
To celebrate the Lunar New Year, thousands of people had previously gathered in the city in Monterey Park.
It’s not yet known how many people were shot or if anyone has passed away.
Social media videos revealed a significant police presence in the region.
The annual Lunar New Year festival lasts for a whole weekend and has in the past attracted crowds of over 100,000 people.
The activities on Saturday night were supposed to wrap up at 21:00 local time.