An arms depot blast which tore through Congo Republic's capital Brazzaville is a reminder that millions of Africans live dangerously close to munitions stored near thickly populated areas, an expert in the field said on Tuesday.

Around 200 people were killed on Sunday in explosions which flattened entire districts of the riverside city. More than 1,300 were injured.

It was the most lethal of a string of such accidents on the continent, following two blasts in Tanzania's commercial capital Dar es Salaam in 2011 and 2009 that together killed around 50. Another one in Maputo in Mozambique in 2007 killed 70 people.

In a region prone to coups and where militaries are short on the vehicles and equipment needed to act fast, many local armies prefer to have their ammunition close to where it is needed and often lack the resources needed to care for it properly.

They're scared they'll have difficulties getting their munitions if they have genuine need of them, so they tend to have their munitions next to their arms, Lionel Cattaneo of the Mines Advisory Group (MAG), a British charity set up to deal with the aftermath of conflict, told Reuters.

Clearly it wasn't ideal to keep them there. They were aware of the problems ... a small amount of this ammunition was due to be destroyed by us this week at the request of the army, added Cattaneo, head of MAG's operations in Congo Republic.

The depot was the largest of its kind in the country, housing operational bombs as large as 250 kg (550 lb). The Congolese authorities had been warned of the dangers of storing munitions near residential areas, Cattaneo said.

When the blast occurred - after a fire triggered by a short circuit, according to the government - it devastated houses and brought down churches and hospitals in the neighbourhood of Mpila and surrounding parts of the city.

On Tuesday, sporadic explosions continued to rock the capital as firemen used water to cool down remaining munitions and put out fires that still blazed inside the army base.

Thousands of homeless prepared for a second night out in the open, while those hospitals still standing received new injured.

Countries including France, Morocco and neighbouring Democratic Republic of Congo sent medical aid. State TV showed children appealing for news of their parents after the blast.

The government declared that the country would be in mourning until all victims were buried.

Cattaneo said the unwillingness of some African armies to get rid of obsolete munitions and a lack of resources to store and maintain them properly meant that many of their depots would remain dangerous.

With all the constraints trying to have the same standards as, for example, in Europe, is a dead end. We're trying to make things better and to bring solutions to up standards to an acceptable level in these depots, he said.

In what reveals the poverty of many Congolese despite their country's oil wealth, MAG said it was getting scores of calls reporting civilians making off with unexploded ordnance.

They don't understand the risk, for them its scrap metal, said Cattaneo. We're particularly targeting schools, children are very curious.

(editing by Mark John/Maria Golovnina)