TOKYO (Reuters) - Dozens of Tokyo firefighters were battling a blaze on Thursday at the world’s largest fish market and one of the capital’s most popular tourist sites, as grey smoke billowed over the city.

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There were no immediate reports of injuries or people trapped, media said.

The 80-year-old Tsukiji fish market draws tens of thousands of visitors a year to its warren of stalls laden with exotic species of fish and fresh sushi, part of a tourism boom that is a key part of Prime Minister Shinzo Abe’s economic plan.

The fire broke out just before 5 p.m. and some 44 fire trucks were on the scene. But efforts to contain the flames were hampered by the area’s narrow streets and tight-knit buildings.

The cause was not immediately known.

The fire was in Tsukiji’s “outer” market - an area packed with informal restaurants where tourists can tuck into fresh seafood plates and sushi.

The flames spread to five buildings covering some 300 square metres later in the evening, media said.

“I hope the area will be able to quickly recover to what it was before,” said Kiyoshi Kimura, president of a company that operates the sushi chain Sushi Zanmai.

The Tsukiji “inner” market, where most seafood wholesalers are located and tuna auctions are carried out at dawn, was not affected.

In June, Tokyo’s governor announced a long-delayed plan to move Tsukiji from its current site on some of the city’s most prime real estate to a man-made island with contaminated soil. The outer market is not scheduled to move.

Tokyo governor Yuriko Koike said the market’s age and vulnerability to a big earthquake meant it had to be rebuilt.