Emergency services were called to the Bilal mosque in Harehills just before 8.45pm on Friday night (July 1) as a fire took hold in the neighbouring community centre.
Crime team investigators returned to the scene this morning but police have now confirmed they are not treating it as suspicious.
“Initial enquiries have led us to believe this is not suspicious and enquiries are ongoing,” a West Yorkshire Police spokesman said.
Nobody is thought to have been hurt in the incident, police added.
“We would like to reassure people that the situation is now under control and the fire service are damping down at the scene,” said Chief Inspector Fran Naughton, of Leeds District, confirming it had not been necessary to evacuate nearby homes.
“The cause of the fire will be investigated by the fire service with the support of the police.
“We are liaising with the centre’s management and we will continue to do all we can to minimise any disruption to the local community.”
The incident happened just before the breaking of the Muslim Ramadan fast, and ahead of the evening’s ‘tarawee’ session (special Ramadan prayers).
Eye-witnesses said they saw smoke before a “big fire” broke out, firefighters from six fire engines called in to help battle the blaze as stunned community members watched from the street.
Mosque leaders told members the cause of the fire was still unknown, reassuring them that evening prayers would still go ahead.
There was concern locally as news spread, with community leaders trying to reassure residents.
Leeds East MP Richard Burgon said on Facebook: “Worried to hear that there has been a fire at the Bilal Centre in Harehills.”
Local Harehills councillor Salma Arif said, also on social media, said: “Fire at Bilal Centre is being contained and as it stands no news on any individuals being caught up in the building.
“Mosque is still accessible via the front entrance.”
Another local resident said there had been “substantial damage” to the community centre building, with firefighters confirming around 40 per cent of the buildling had been destroyed.