At least 37 people, including two pregnant women, were burned to death after a blast at an illegal oil refinery in Rivers State, a local security official and community leader said on Tuesday.

Illegal refining is common in the oil-rich Niger Delta region of Nigeria as impoverished locals tap pipelines to make fuel to sell for a profit. The practice, which can be as basic as boiling crude oil in drums to extract fuel, is often deadly.

The latest incident happened in the early hours of Monday in the Ibaa community, in Rivers State, Rufus Welekem, the head of security in the community said.

A Reuters witness saw charred remains of 15 people at an open space surrounded by burnt palm trees and a motorbike.

"Thirty five people were caught in the fire. Two people who were lucky to escape also died this morning in hospital," said Welekem.

Relatives had identified some of the victims and taken them for burial, he said.

Nigeria has for years tried to clamp down on illegal crude refineries, with little success, in part because powerfully connected politicians and security officials are involved, local environmental groups say.

Crude oil theft, pipeline vandalism and legal battles over oil spills are pushing oil majors operating in Nigeria to sell their onshore and shallow water assets to concentrate on deep water operations.

Reuters