A 43-year-old man was in critical condition after being attacked with a machete while riding his bicycle early Sunday morning in Westlake, authorities said.
Four people were being sought in connection with the attack, which occurred near the intersection of 11th Street and Burlington Avenue, said Sgt. Melvin Gamble of the Los Angeles Police Department.
The assailants were described only as young male adults. One of them was armed with a machete when they approached the bicyclist on foot about 12:35 a.m., the sergeant said.
The man lost a significant amount of blood and suffered a fractured skull after the armed person struck him on the head and hands with the large knife, according to police.
"The victim suffered lacerations to the right hand and a severed thumb from the left hand," said Officer Stacey Vandersall, an LAPD spokeswoman.
Witnesses called 911 after hearing the victim scream. They told investigators that the attackers took the bike and fled the scene in a dark green, older-model vehicle. No other descriptions were given.
The victim was transported to a hospital with moderate to major injuries, and his wounded hand may have to be amputated, Gamble said, adding that he was expected to survive.
Authorities initially told KTLA the man was 18 years old. But later in the afternoon, Sgt. J. Marroquin with LAPD's Rampart Division stated the victim was 43 years old.
The incident was believed to be gang-related, according to police.
KTLA's Feven Kiflegiorgis contributed to this story.