Seven sailors have died after inhaling toxic gases while repairing a floating dry dock in the Amazon port of Iquitos, Peru's navy said.

A statement by the navy's industrial services unit said the deaths Tuesday night were under investigation.

It said the dry dock malfunctioned as it was being maneuvered to allow entry of a vessel.

The sailors went into the dry dock's tanks to get to the source of the problem when they were overcome by toxic fumes, the statement said.