(CNN) -- Royal Caribbean Cruises cut short a seven-day Alaska cruise aboard its Celebrity Millennium and canceled four of the ship's upcoming trips because of a problem with the motor, a company spokeswoman said Wednesday.
The Millennium was carrying 2,200 guests and 958 crew members when the motor experienced a "technical issue" Sunday, spokeswoman Cynthia Martinez said. The captain decided to return to port at Ketchikan, Alaska, to evaluate the problem, and the company ultimately decided to cancel the rest of the trip.
"It is important to note that the ship can sail at a reduced speed with only one motor," Martinez said. "However, in an abundance of caution, we have decided to cancel the sailing and have the repairs made at the shipyard immediately. The safety of our guests and crew is always our highest priority."
Millennium left Vancouver, British Columbia, Friday and was due to make stops at the Alaskan ports of Juneau and Skagway before ending in Seward in two days.
Several charter flights have already departed Ketchikan to take passengers back to the Pacific Northwest, Martinez said.
The company canceled cruises departing on the following dates:
August 23, 2013 -- from Seward to Vancouver
August 30, 2013 -- from Vancouver to Seward
September 6, 2013 -- from Seward to Vancouver
September 13, 2013 -- from Vancouver to San Diego, California
Passengers booked on the canceled cruises will receive a full refund and a certificate for a future Celebrity cruise, the company said.
CNN's Chuck Johnston and Amanda Watts contributed to this report.