At least three ships are on fire at an industrial ship plant in Iran's southern city of Bushehr, according to the official IRNA news agency.
The Tasnim agency says the number of ships that caught fire is seven.
Videos from the scene have been shared online.
No injuries have so far been reported. The cause of the fire is still unknown.
Last week, a container ship caught fire in Ameri Port in Tangestan County, also in Bushehr.
A series of fires and explosions have taken place at Iran's industrial and military facilities since late June.
On 2 July, a blast occurred at the Natanz nuclear site, which is Iran’s primary uranium processing facility.
No casualties or leaks of radioactive materials were reported after the blast. However, reports emerged citing unnamed Iranian officials suggesting that Israel was responsible for the blast at Natanz.