(CNN)Sections of Venice Beach in Los Angeles were blocked off Sunday after authorities discovered needles and other medical supplies had washed up on shore.
Lifeguards found a "large amount" of medical supplies around 11:30 a.m. PST along the beach south of the Venice Beach Pier, according to tweets from the Lifeguard Division of the LA Fire Department.
Authorities said on Twitter they did not know where the medical supplies and needles came from. Lifeguards continued to search the beach and will monitor the area "for the safety of public use until the investigation and cleanup are complete," the LA Fire Department said.
Lifeguards said they also alerted other agencies, including the LA County Department of Public Health, US Coast Guard and police.
Venice Beach, west of Los Angeles and just south of Santa Monica, is known for its canals, trendy shops and colorful boardwalk.