A media crew saw around 30 armed men at the Hotel Moscow yesterday, most of them wearing balaclavas and wielding Kalashnikov assault rifles.
At the hotel, where many journalists covering the referendum are staying, one gunman told reporters: "We already smashed one camera, do you want us to break another one?"
Another threatened a photographer with his rifle butt and a third pointed a gun at reporters trying to go up stairs.
The security operation lasted around an hour and officials at the scene gave conflicting reports about why the gunmen were there.
"It was a false alarm," said Valeriy Kuznetsov, defence minister in Crimea's regional parliament.
"We were looking for something bad but we did not find anything," he said.
But Olga Kondrashova, a police spokesperson, said it was "a planned training exercise".
