Parish Priest Father Jeremy Trood had just finished a requiem mass for a mother and daughter at St Aloysius Church on Phoenix Road, near Euston station, when the drive-by shooting took place outside on Saturday afternoon.

Six people were injured in the incident, including a seven-year-old girl who remains in a stable but critical condition, and a 48-year-old woman who suffered potentially life-changing injuries.

A 22-year-old man has been arrested on suspicion of attempted murder, police said in the early hours of Monday.

Mr Trood said he heard the gunshot shortly after mourners left the church to release doves outside.

"I was inside the church and suddenly there was an enormous bang and people rushed back into the church screaming and saying shots had been fired," he said.

"There are no words that can describe what had happened and I can't imagine why anybody could possibly do such a thing. There were hundreds of people in the church coming out. It was pandemonium."

Father Trood said some people took shelter in the church.

"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," he added.

As well as the seven-year-old girl and 48-year-old woman, three other women - aged 21, 41 and 54 - and a 12-year-old girl were also injured in the attack.

The 12-year-old suffered leg injuries but has since been discharged from hospital, police have said. She is expected to make a full recovery.

Superintendent Jack Rowlands, from the Metropolitan Police, said the force believes a gunshot was fired from a moving car at about 1.30pm before it drove away from the scene.

He described the incident as a "senseless act of violence".

People who attended the memorial service at the church in Phoenix Road told Sky News they do not know why it happened.

The shooting took place after the ceremony held in memory of 20-year-old Sara Sanchez and her mother, Fresia Calderon, who died within a month of one another in November.

Ms Sanchez died following a battle with leukaemia, while her mother Ms Calderon died suddenly from a rare blood clot on arrival at Heathrow from Colombia, MyLondon reported.

Those who knew the mother and daughter said those hurt in the incident were attending the service in their memory.

London Mayor Sadiq Khan described the attack as a "deeply distressing incident".