The number of dolphins found dead in Mauritius, where the sea has been polluted following a huge oil spill last month, has risen to 25, causing more sadness and anger among locals.

A further seven dead dolphins were found on Thursday morning by residents off the south-east coast in Grand-Sable and Pointe-aux-Feuilles.

The mammals have been sent for a post-mortem examination to establish the cause of death.

A total of 18 dead dolphins had swept to shore on Wednesday, with environmentalists blaming their deaths on the oil spill caused by a Japanese-owned vessel that ran aground on coral reef on 25 July.

The fisheries minister said that "at first glance" their deaths did not appear to be connected to the spill.