Twenty-two passengers traveling on a Carnival cruise ship for the trip of a lifetime instead got the scare of a lifetime when they were robbed at gunpoint while on an excursion in the Mexican resort town of Puerto Vallarta.

The passengers were robbed Thursday during a guided trail excursion while on a seven-day cruise aboard the Carnival Splendor, the Miami-based cruise line confirmed in a statement released Saturday.

No one was injured and the guests returned safely to the ship, according to Carnival, which did not provide any further details of the robbery except to say the company is assisting guests to reimburse them for lost valuables.

"Carnival sincerely apologizes to its guests for this very unfortunate and disturbing event and is providing its full support and assistance," the company said in the statement.

The 3,006-passenger ship departed from the port of Long Beach Feb. 19 for a seven-day Mexican Riviera cruise that included a stop in Cabo San Lucas as well as Puerto Vallarta, according to the ship's online itinerary.

The cruise line has suspended the nature trail tour where the robbery occurred, one of about 35 excursions the ship offers passengers while docked in Puerto Vallarta, according to the Carnival website.

The U.S. State Department two weeks ago issued a travel warning to Americans to avoid unnecessary travel to 14 Mexican states because of increased violence in the country.  Included in the list is the state of Jalisco, of which Puerto Vallarta is one of the largest cities.

The Los Angeles Times cites Mexican newspapers in reporting that hooded gunmen intercepted the tourists' bus about 5 p.m. Thursday as it returned from the pueblo of El Nogalito.  The gunmen took cameras, money, watches and other valuables from passengers before fleeing, the paper said.

The Carnival Splendor is the same ship that left passengers stranded off the coast of San Diego in 2010 when a fire erupted in the ship's engine room.

The Splendor is also a sister ship of the Costa Concordia cruise ship that sunk off the coast of Italy last month, killing 32 passengers.  Both ships are owned by parent company Carnival Cruise Lines.

The Associated Press contributed to this report.