At least 29 people were killed, including 11 children, at a stampede during an all-night crusade in Liberia on Wednesday.

The open air gathering was held at a Pentecostal church in the New Kru Town neighbourhood on the outskirts of capital city, Monrovia. 

The revival was being hosted by Liberian preacher Apostle Abraham Kromah, of World of Life Outreach International. 

Some of the survivors were critically injured. 

In the wake of the tragedy, President George Weah announced three days of mourning. 

"This is a sad day for the country," Deputy Information Minister Jalawah Tonpo told state radio.

Police officials told the BBC that the stampede was triggered by a street gang entering the revival after a collection of offerings.

One person who had been at the event, Exodus Morias, told Reuters that the gang members were armed.

"We saw a group of men with cutlasses and other weapons coming toward the crowd," Morias said. 

"While running, some people dropped and others fell on the ground and walked over them."