Suspects fired a shotgun from a moving car at mourners gathered outside a church in north London, police have said.
Superintendent Jack Rowlands of the Metropolitan Police described the shooting as a “senseless act of violence” and said officers were looking for a 2019 model black Toyota.
Several people were injured after the drive-by shooting near a memorial site for a young woman who died of cancer.
A seven-year-old girl is in a stable but life-threatening condition in hospital. A 48-year-old woman suffered potentially life-changing injuries.
Witnesses described how the attack sent people running and screaming from St Aloysius Roman Catholic Church in Euston, central London, on Saturday afternoon.
The seven-year-old girl, another aged 12 and four women, aged 21, 41, 48 and 54, were taken to hospital after the incident at around 1.30pm.
The 12-year-old suffered a leg injury and has been discharged from hospital. She is expected to make a full recovery.
It happened as a requiem mass for 20-year-old Sara Sanchez and her mother, Fresia Calderon, who died within a month of one another in November, took place inside the church in Phoenix Road.
Father Jeremy Trood, who conducted the service, described the moment the gunshots were heard.
“I was inside the church. I heard the bang and people ran back into the church,” he said.
“They knew something had happened outside.
“They were very scared, people sheltered in the church until the police said they can leave, but some of them were so scared they had to wait a while to get their confidence back up to go outside.”
Queen Macauley was visiting a friend who lives near the church when she heard the gunshots.
She told Sky News her “heart was racing” as she saw people running and heard screams.
“It was quite chaotic,” she added.
One resident of an estate across the road from the church, who did not want to be named, also heard gunshots.
“I was having a quiet day on my balcony and I heard this almighty bang and I thought this was not normal,” they said.
“The next minute, everyone was screaming and shouting. We have a food bank there and everyone was running off.
“Neighbours came in and said there has been a shooting. What a terrible thing.”