An Islamic State banner appeared on the website of the historic Montauk Manor on Saturday, in an apparent hacking that may have affected other websites across the country, according to police and staff at the condo complex.

Sometime on Saturday, a black banner declaring "Hacked by Islamic State (ISIS)" and "We Are Everywhere" appeared at the top of the East End landmark's website. The message was still up late Saturday night.

"We've been told that we're one of 800 sites that's been affected by this," said Kathy Surrey, night manager for 140-unit condominium complex.

"It's been a fun day," she said. "I don't mind the advertising, but this isn't good advertising."

East Hampton Town Police Sgt. Joe Kearney said the department was alerted to the message around 4 p.m. "We went to the manor to speak to them," he said. "We're aware of it. We're still investigating it."

Similar messages appeared this week on websites for companies based as far away as Mississippi, Missouri and Ohio, according to news reports.

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The Montauk Manor, a Tudor Revival-style building built in 1927 atop Montauk's Fort Hill, was once an attraction for the rich and famous who summered on the East End. The castle-like structure still houses summer visitors and year-round residents.

Surrey said the company that hosts the Montauk Manor website was working on taking the site down Saturday night.

She said residents of the complex have called the front desk throughout the afternoon as they discovered the message.

"One guy called down to say he was a karate expert," she said. "If we needed him."