At least 12 people -- mostly minors -- have been confirmed dead after a boat capsized Sunday afternoon in the southern Nigerian commercial capital Lagos, according to government officials and emergency workers.

"An unfortunate incident occurred at Ilashe today Sunday Aug. 20th arising from an overloading of passengers on a Banana boat taking off from an illegal jetty," the managing director of the Lagos State Inland Waterways Authority (LASWA) Abisola Kamson said in a statement.

"Four people are receiving treatment in the hospital. The LASWA rescue team has been on the ground and the search is still ongoing," Kamson added.

A spokesman of the National Emergency Management Agency (NEMA) Ibrahim Farinloye told Anadolu Agency that the boat involved was a "private one and none of the victims had life jackets".

Farinloye said a probe has been launched into the incident, adding that the victims were going to church when the accident occurred.