Muslims have been asked to remain calm as police held a man on suspicion of murder hours after a religious leader was left for dead from a brutal attack on his way home from prayers at a mosque.
The victim, named locally as Jalal Uddin, was found with head injuries in a children's play area on South Street in the Wardleworth area of Rochdale on Thursday night.
Detectives say a racist motive for the murder has not been ruled out but they are still investigating, with a 31-year-old man in custody.
Local religious leaders have called for calm, asking for police to be allowed to do their work and for locals not to speculate about what prompted the attack.
It is thought Mr Uddin, whose family is believed to be in Bangladesh, was on his way home from a friend's house, after earlier visiting a mosque, when he was assaulted between 8.40pm and 8.55pm.
It is believed he was taking a shortcut through the playground on his way home after eating dinner at the friend's home.
He was well known locally, and acted as a Qari, or a reciter of the Koran, at the Jalalia Jaame Masjid mosque.
A major investigation has been launched by Greater Manchester Police (GMP) and a heavy police presence remains in the area, with the sight of the attack cordoned off as forensic officers continue the hunt for evidence.
Dobir Miah, chief officer for the Rochdale Council of Mosques, said: "GMP are working closely with the Rochdale Council of Mosques and we remain in contact with police to offer any assistance to the investigation.
"We would like to urge people to please remain calm and be reassured that everything possible is being done to find out what has happened.
"Nothing has been said that suggests there is an immediate threat to people doing their day-to-day activities."
Assistant Chief Constable Rebekah Sutcliffe said: "The investigation is at a really early stage and I must stress that. A man is in custody and has been arrested but at the moment we are keeping a completely open mind as to what the motive for this attack is.
"I think it would be unhelpful at this stage really to speculate as to what has happened.
"We really do not know what the motive for this assault was and we are really keen to understand that, and we do need people to come forward and talk to us."
Ms Sutcliffe said detectives are looking at the possibility that the incident was racially motivated but added: "At the moment we just cannot say one way or the other."
Police and paramedics were called at about 9pm after a member of the public found the victim critically injured.
He was taken to hospital but died shortly after from his injuries. Police have not yet formally identified the victim.
A Home Office post-mortem examination will take place later.
In a statement on its Facebook page, the Jalalia Jaame Masjid mosque said: "It is with deep sadness we inform you that our dear Qari Jalal Uddin Saab passed away last night.
"The cause of his death is yet to be confirmed, we recommend that you do not speculate but rather wait for the facts to be established by the police.
"Instead we urge you to raise your hands and make sincere dua for our beloved Qari Saab.
"There is not a day that would go by without seeing Qari Jalal Uddin at the masjid Subhan'Allah."
A visible police presence was on site around a huge cordon surrounding the area which contained forensic tents.
Officers were dotted around the cordon which also takes in the Bilal Jamia Masjid mosque in Bulwer Street, where Mr Uddin is thought to have attended for evening prayers.