Four Nigerian villagers and an environmental group are demanding oil company Shell take responsibility for damage from oil leaks caused by its Nigerian subsidiary, lawyers said. In letters sent to the company, Royal Dutch Shell PLC is accused of negligence for improperly maintaining equipment and failing to clean up spills that devastated their crops and fish farms in the Niger Delta. The villagers and the Friends of the Earth say that if Shell does not acknowledge responsibility they will file suit in Dutch courts seeking to clarify responsibility and win damages. "This is the first time a Dutch company would be held liable for damage by a daughter operation in another country," said Anne van Schaik, of the Dutch branch of Friends of the Earth, which is a party to the case. A Shell spokesman in Rotterdam, Andre Romeyn, said Wednesday that he had not yet seen the letters. Shell would need to study them before deciding whether to publicly respond, he said.