An explosion at an underground coal mine in northeast Colombia killed 20 workers on Wednesday, officials said, in the latest accident to hit the mining industry in Latin America.

Colombia is the world's No. 5 coal exporter, with an industry dominated by open-pit thermal players, but smaller mines in the centre of the Andean nation usually work underground where methane gas build-ups can cause accidents.

An official at the mining regulator Ingeominas said the latest blast, in Norte de Santander province, was probably caused by methane.

They've just told me there are 20 dead and six wounded, Marisa Fernandez told Reuters by telephone.

Local officials and Colombia's Red Cross said five bodies had been recovered.

Yamile Rangel, mayor of Sardinata municipality, said 16 people were still trapped in the mine but Red Cross officials said there was little chance of them being alive.

The explosion was the latest in a series of mine accidents round South America, including a collapse in Chile in August that buried 33 workers until they were rescued to international jubilation after two months underground.

In June, a blast killed 70 miners in Colombia and, in November, nine people died at two small coal mines in Colombia's Cundinamarca province.

Despite the recent run of accidents, conditions for workers in Latin America's mines have improved radically in recent decades from the nightmarish conditions of past centuries after Spanish conquistadors began a hunt for gold.

The modern-day industry has helped fuel an economic boom in some nations, including Colombia, where mining is one of the main generators of foreign exchange.