Major cruise lines are altering their routes to avoid Category 4 hurricane Florence, which is likely to strike the US east coast on Thursday.

Norwegian Cruise Line's Norwegian Escape was diverted to the Bahamas instead of Bermuda, reported USA Today.

The ship departed New York City on Sunday for what was supposed to be a three-day visit to Bermuda's King's Wharf. Instead it will call at Nassau and Great Stirrup Cay in the Bahamas as well as Port Canaveral, Florida.

Royal Caribbean's 2,446-passenger Grandeur of the Seas and Carnival Cruise Line's 2,124-passenger Carnival Pride were also rerouted to the Bahamas this week instead of Bermuda.

Another Carnival ship, the New York-based, 3,936-passenger Carnival Horizon, cancelled a Sunday call at San Juan, Puerto Rico and shifted the date of a call in the Dominican Republic as it altered its route to stay out of the storm's way.

It is due back in New York on Thursday.

Hurricane Florence also affected the itineraries of Norwegian Cruise Line's Boston-based Norwegian Dawn and two vessels operated by Oceania Cruises.

In a preemptive move, the 2,340-passenger Norwegian Dawn sailed for Canada and New England on Friday instead of Bermuda and is in the midst of unexpected stops in Halifax and Sydney, Nova Scotia; St. John, New Brunswick; and Bar Harbor, Maine.

Oceania's 684-passenger Sirena is bypassing Bermuda as it nears the end of a repositioning cruise from Europe to Miami while sister ship Insignia is shifting several port calls.

Hurricane Florence is expected to cause life-threatening storm surge, destructive winds and massive inland rainfall flooding, local news reports said.

As of noon on Monday, Florence was more than 1,200 miles east-southeast of Cape Fear, North Carolina, moving westward.