BUENOS AIRES - An Argentine man has been arrested on suspicion of murdering at least six people after making a pact with a spiritual figure known as San La Muerte (Lord of Death), police say.

Marcelo Antelo was captured after a shootout in the capital, Buenos Aires.

The 22-year-old had apparently promised to kill one person a week in return for protection and prosperity.

San La Muerte is said to have a large following in the country's prisons and shanty towns.

The BBC's Daniel Schweimler in Buenos Aires says the spirit's followers ask for favours, such as to win a fight or protect a harvest, but they also use it to request the death of an enemy.

The figure evolved in poor communities in the north of Argentina, where characters from traditional indigenous religions merged with elements from Roman Catholicism, our correspondent adds.

The authorities are charging Mr Antelo, also known as Marcelito, with six murders, but say they are investigating possible links with a number of other unsolved killings.

"The murderer had made a pact with San La Muerte, by which he had promised one murder each week to obtain protection for him and his family," police sources told AFP news agency.

Five of his alleged victims have been identified, but a sixth was burnt beyond recognition.

Our correspondent says the killings have, until now, attracted little attention in the Argentine media since the victims were poor, marginalised people living in an area where even the police often dare not venture.