Tour firms in Russia’s Far East say military drills off the Kamchatka Peninsula are costing them tens of millions of rubles in lost revenue due to closures of key maritime routes during peak tourist season.

The Kamchatka Tourism Industry Association (KTIA) said Tuesday that naval exercises by the Russian military have already led to more than 50 million rubles (over $635,000) in losses for local businesses.

Russia’s Defense Ministry announced that the naval drills, involving 40 warships, 30 aircraft and more than 5,000 troops in the Pacific Ocean, would run from June 16 to June 30.

But KTIA said vessel traffic had been halted and Avacha Bay, a major area for sightseeing cruises, had been closed since last Friday without warning to operators.

“People usually book tours three or four months in advance. We didn’t know about the drills until we were suddenly told the sea was closed,” KTIA chairwoman Yelena Lassal told the Telegram news channel Govorit Nemoskva.