This is a very unusual mosque for what I’ve seen. Its inside the port of this big enterprise called SOPAC PP, the first fish exporter in Mauritania.
Islam is the official religion of Mauritania. Despite ethnic and cultural differences among Mauritanians they are all bound by a common Muslim attachment to the Malekite sect. Its a country with 100% Muslims.
The images you have of these places are amazing, it sounds a very interesting place