The cause of a fire that damaged a section of the Portland Pier on Wednesday night is under investigation by the Portland Fire Department.

Deputy Fire Chief Terry Walsh said the fire was reported around 9 p.m. It took crews from the city’s fireboat and from the mainland more than an hour to bring the fire under control because it started in an area between the planks on top of the pier and the crossbeams underneath it.

“We had to fight the fire from above and below,” Walsh said.

Although the damage was limited to a small area, that section of the Portland Pier will remain closed until repairs can be completed. The fire damaged the end section of the pier that juts into the harbor, just beyond J’s Oyster off Commercial Street.

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