RNA - The victim is reported to have been the person chosen to lead and recite the call to prayer.
“A man was found with stab injuries,” police said in a statement. “He was treated by paramedics before being taken to hospital. We await an update on his condition. A man was arrested at the scene on suspicion of attempted murder.”
In a video clip of the incident, uploaded by an eyewitness, the suspect is seen on the floor with no shoes on, suggesting he removed his shoes inside the buildings as those praying in Mosques typically do.
In another video of the incident, uploaded by an eyewitness, a young white man in a red hooded top, is seen being led from the mosque by police.
In a separate video a bladed weapon, less than 10cm in length, can be seen discarded on the floor.
One man who uploaded videos from the scene tweeted: "This is absolutely terrible.
"No Muslim is safe in their places of worship!!"
Mohammed Shafiq, CEO of Islamic community group the Ramadhan Foundation, said: "I pay tribute to local Muslims and police officers who stopped and controlled the situation which otherwise could have escalated.
"Whilst we await the full facts, one thing is clear Islamophobia is real and a threat to cohesive communities.
"At a time when Islamophobic figures are given a media platform we should not be surprised by lunatics using guns to kill people.
"In light of the heightened alert and concern of British Muslims the Ramadhan Foundation have written to all Mosques in the United Kingdom to step up security around Friday prayers.
"We are in communication with Imams and Prayer Leaders to offer our support and solidarity."
Less than a year ago the mosque was affected by another stabbing incident.
Kamal Hussain fled to London Central Mosque after killing Zahir Visiter on 28 March, sparking an armed raid.
He was acquitted of murder at the Old Bailey but found guilty of manslaughter.
London Central Mosque is one of the country's largest and can hold 5,000 worshippers, with people from across London travelling to it for prayers.
Although the incident has not been declared a terrorist incident, the Met's SO15 counter terror unit are looking into it.