Police in Huntington Beach, California, declared an unlawful assembly late Saturday over what they described as an "unruly" beach party.

The event was reportedly promoted on TikTok and attracted at least 1,000 attendees. 

Police warned partygoers Saturday afternoon that the beach would close at 10 p.m. but as of early Sunday, many of the revelers remained and had spilled into the downtown area. 

Huntington Beach is in Orange County, about 36 miles south of Los Angeles.

An emergency curfew was put into place until 5:30 a.m. PT Sunday, police said. 

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The party apparently started as an online birthday invitation that quickly went viral, trending with the hashtag #adrianskickback, according to FOX 11 in Los Angeles. Some people even came in from out of state for the event. 

Officers began to disperse partiers when some climbed on top of beach lifeguard towers and started setting off fireworks, the Orange County Register reported. 

The fireworks sparked a degree of panic as many people went running for safety, KABC-TV of Los Angeles reported.

At least one person was reportedly arrested but no other details were given.

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Police also declared an unlawful assembly Friday night when about half of Saturday’s numbers turned out to party, the newspaper reported.