Police later determined the threat was a hoax.
“The ferry has been evacuated and we have staff on site to evaluate the situation,” said Towe Hägg of the Stockholm police to news agency TT soon after the alarm came through.
Police were alerted about the threat just after midday. Officers were quickly on the scene to evaluate the seriousness of the situation.
According to daily Aftonbladet, the threat came from an English-speaking man who said that the boat would blow up.
The threat allegedly was received to the shipping company's St. Petersburg office.
The ferry staff aboard the Anastasia told police that the number of passengers who were taken off the evacuated boat numbered between 100 and 200.
Around 1.30pm the officer in charge decided that the threat wasn't serious and that the passengers could re-enter the ferry.