Sunday morning is usually the preserve of Christian pastors in the Nigerian megacity of Lagos but a new form of worship is emerging to challenge the monopoly.
"Praise Allah!" shouts the imam of the Nasrul-lahi-li Fathi Society of Nigeria (NASFAT) before thousands of his faithful, gathered under tents on the outskirts of the city.
Pacing up and down through the crowd, he punctuates his message with vigorous "Allahs" in the trademark bombastic style of Nigeria's evangelical preachers.
Entranced, men and women sitting on multi-coloured prayer mats, raise their hands to the heavens.
NASFAT is one of a growing number of groups practising "charismatic Islam" in response to the massive success of pentecostal Christianity in Nigeria, said Ebenezer Obadare, a sociology professor at the University of Kansas.
It has introduced "new modalities of prayer, modes of proselytising, and repertoires of devotion that closely approximate forms normally exclusively associated with Pentecostal Christianity," he told AFP.
NASFAT's mission statement is "to develop an enlightened Muslim society nurtured by a true understanding of Islam for the spiritual upliftment and welfare of mankind".
Along with traditional Friday prayers, it holds a special session every Sunday morning.
"The aim is to maximise favourably the leisure time that exists among Muslims who laze away on Sunday mornings," NASFAT explains on its website.
Unofficially, it also stops them from being invited to Sunday services at neighbouring churches -- even if the movement doesn't admit it.
- Wave of conversions -
"Friends invited me for the Sunday prayers," said Sheriff Yussuf, a well-dressed man in long white robes who joined the movement in 1998.
"At the beginning I was very sceptical but then I thought, 'let me try, I'm not doing anything on Sundays'.
"It creates an attraction to Islam, to start pulling Muslims out of the churches."
NASFAT and other charismatic Islam groups born in its wake have been embraced by the Yoruba community, which is traditionally based in the southwest and one of the few ethnic groups in Nigeria not to be attached to a particular religion.
In fact throughout southwestern Nigeria, a single family can celebrate Muslim festivals such as Eid as well as Christian ones such as Christmas.
It's not uncommon to hear a Muslim release an enthusiastic "amen" or listen to the latest hit gospel song in a taxi decorated with quotes from the Koran.
But the siren song of charismatic Christian churches in Lagos -- financial prosperity, miraculous healing, eternal fertility and a faithful soulmate -- is just too strong for many to resist and conversion to Christianity is very common.
So instead of fighting the evangelicals, a handful of wealthy bankers from Ibadan, 130 kilometres (80 miles) northeast of Lagos, decided it would be better learn from their competitors.
- Growing popularity -
"We were gathering on Sunday to talk about the Koran, this is how it started," said Musediq Kosemoni, who was one of the seven founder members of NASFAT in 1995.
"In three, four weeks, we started seeing an increasing number. It wasn't a planned thing, no-one can explain."
NASFAT now boasts hundreds of thousands of faithful, with branches not only in Nigeria but also in England, Canada, Germany and the Netherlands.
The movement, which encourages both Islamic and "western" education, first targeted the young, educated Yoruba upper class.
But it is now becoming popular among all levels of society and even has its own university.
"They're unique. They want to get every Muslim, men and women, educated, to enlighten them in order to take them out of poverty," said Lateef Adetona, head of the religious studies department at Lagos State University.
"They think that the Salafists -- a more conservative school -- are discouraging people to turn to Islam."
NASFAT hasn't gained traction in the Hausa-speaking community in northern Nigeria, which represents the majority of Muslims in the country and dismisses the southwest school.
However, NASFAT says that despite their different approaches, they share the common goal of drawing people to Islam.
"We are going against the ones who give Islam a bad name," said chief missionary Abdullahi Gbade Akinbode, arguing that NASFAT offers a better alternative than the hardline sectarian view of Islam espoused by Boko Haram jihadists.
"We organise summits against radicalisation, against Boko Haram, to educate our people," said Akinbode.
The missionary discreetly passes a copy of the NASFAT prayer book.
On the cover, the group's slogan reads: "There is no help except from Allah."