A Seattle-area ferry struck a whale Tuesday evening, a spokeswoman for Washington State Ferries said.

The animal was hit about 8:15 p.m., minutes after the ferry left Seattle for Bainbridge Island, west of the city, said spokesperson Dana Warr, who was not sure what kind of whale was hit.

The ferry was traveling about 17 mph when it struck the whale just after the animal had surfaced about five feet in front of the ferry’s bow.

"There had been no previous reports of whales spotted in Elliott Bay earlier today," Warr said in a statement, adding that the Coast Guard, the National Oceanic and Atmospheric Administration and marine mammal agencies were notified.

Several passengers aboard the Wenatchee ferry said they saw a bleeding whale from the passenger deck, NBC affiliate KING of Seattle reported, and one witness told the station it was likely a gray whale.

"The whale surfaced after being struck and gushing a lot of blood," Beth Andrus of Seattle told The Seattle Times newspaper. "It surfaced a few more times before sinking.”

The animal's condition was not known, and boats were seen looking for the whale, KING reported. No injuries to anyone on the ferry were reported.

The Coast Guard investigated with a response boat, and a helicopter was also sent out to look for a whale, which had not been located late Tuesday night, Coast Guard Petty Officer Trevor Lilburn said.

"We are aware of the reports that a Washington State Ferry hit a whale in Elliott Bay tonight. We have asked the U.S. Coast Guard to assist in locating the whale that may have been struck and are standing by for further information," a NOAA spokesperson said in a statement to KING.

Gray whales can grow up to about 49 feet long and approximately 90,000 pounds, NOAA says.

NOAA says on its website that gray whales, found mainly in shallow coastal waters in the North Pacific Ocean, are known for their curiosity toward boats and face threats from vessel strikes, especially because they feed and migrate along the U.S. west coast.

The whales make one of the longest annual migrations of any mammal with a round trip of around 10,000 miles, according to the agency.