Tensions flared Monday in the immigrant neighborhood of Westlake as dozens of protesters and Los Angeles police faced off at the site where a day laborer was fatally shot by police a day earlier.

The angry crowd gathered at 6th Street and Union Avenue, a bustling corner where Los Angeles Police Department officers said they were confronted Sunday by a knife-wielding man who refused commands to drop his weapon.

The protesters, claiming the man was unarmed, used a bullhorn to shout in Spanish — “Assassination!” “Assassination!” and “We want justice!” — as they marched along 6th to the Los Angeles Police Department’s Rampart station. Onlookers watched from their apartment windows, while others joined the procession as LAPD officers monitored the action from nearby corners and adjacent streets.

At one point, police in riot gear faced off with a shouting throng near a series of memorials hung from a fence by the sidewalk where the man was killed on 6th Street. He was identified by friends as Manuel Jamines, 37, a Guatemalan immigrant who came to Los Angeles seven years ago.

“He was not a criminal,” said Juan Velasquez, who said he is from the same village as Jamines.

Julio Martinez, 57, said he was walking along 6th on Sunday when he saw officers from the LAPD’s bicycle unit fire their weapons at Jamines, who was not armed, according to Martinez.

“I did not see a knife in his hands,” Martinez said, adding that he heard two gunshots.

LAPD Capt. Rigo Romero said officers recovered a knife from the scene and that detectives were investigating the killing.

“Our investigation is going to be transparent,” he said. “We take every force investigation very, very seriously.”

At one point, protesters got into a shouting and shoving match with a store security guard, who fled to his car and sped away as people hurled objects and kicked at his vehicle.

As the crowd gathered at the corner, Guatemalan Consul General Pablo Garcia Saenz arrived to ask that people protest peacefully and assure them that his staff was in contact with the LAPD. His assistants said that a community meeting was planned for 7 p.m. Tuesday at the Guatemalan Consulate.

“We do not want any more violence,” Saenz told the crowd in Spanish.

robert.lopez@latimes.com