Police officers were diverted from the Queen’s funeral to deal with widespread disorder in Leicester after a cricket match between India and Pakistan.
Leicestershire Police said a number of resources were provided to them, with extra officers deployed from the West Midlands, Derbyshire and Nottinghamshire.
Horses from Thames Valley Police were also deployed in the city, the force added.
Police said the extra assistance was provided through the normal mutual aid process and some officers were diverted from going to London to help.
The widespread disorder has led to 47 arrests, with a faith leader saying it was sparked by a “country-based dispute” after the cricket.
Amos Noronha, 20, was sentenced to 10 months in prison after pleading guilty to possession of an offensive weapon in connection with the violence.
Suleman Nagdi, from the city’s Federation of Muslim Organisations, told the PA news agency it was the first time he could remember the communities becoming violent.
The violence is believed to have been between Muslim and Hindu communities, with Mr Nagdi saying “loyalties kicked in” after the cricket.
Two arrests were initially made when police said disturbances broke out at an unplanned protest on Saturday night and Sunday morning.
In a statement confirming the first 15 arrests, Leicestershire Police said: “Officers became aware of groups of young men gathering on Sunday afternoon in the North Evington area of the city.
“Officers spoke to them and took steps, including putting in place a temporary police cordon, to minimise harm and disturbance to communities.”
It is usually younger people who are involved in it - hopefully we can connect with their parents— Suleman Nagdi
The force added that all 15 remained in policy custody just past midnight on Monday morning.
Temporary Chief Constable Rob Nixon called for calm on Saturday night.
On Sunday, 18 people were arrested for offences including affray, common assault, possession of an offensive weapon and violent disorder.
Proactive patrols are continuing in the area, with the force describing the violence as “unacceptable”.
Mr Nagdi told PA: “We always say the global impacts the local.
“The start (of the disorder) was the cricket match – it is a country-based dispute.
“It is usually younger people who are involved in it – hopefully we can connect with their parents.”
Addressing the police response, Mr Nagdi said: “I am sure the resources have been stretched and we also understand the constraints they are under.
“By and large, the police have kept us informed, they have kept us connected.”
