(4:08 p.m. BST) -- Fred. Olsen Cruise Lines has paused all its ocean operations indefinitely and cancelled the first five sailings aboard its European river cruise ship, Brabant.

On March 13, Fred. Olsen stated it would resume operations on May 23, but in a prepared statement released today the line said it could not give a return date.

Peter Deer, Managing Director at Fred. Olsen Cruise Lines, said:

"At this stage I am not able to confirm a date when we can expect to resume normal operations, as what I don’t want to do is set an expectation and not be able to deliver what we promise.

"What I can say is that we are keeping a very close eye on the latest guidance from the relevant authorities, including the UK Government and Public Health England, as well as overseas policies.

"We are very clear on our position that we will not resume cruising until we know that it is safe for us to do so. The safety of our guests and crew is always our utmost priority, and this is especially true now. All guests on affected cruises will be notified with at least 30 days’ notice before their cruise was due to depart.

"It is regrettable that we won’t be welcoming guests back on board at the end of May as we had initially hoped, but we can’t wait to start sailing again as soon as the world is ready for us to do so."

Fred. Olsen is offering a full refund or a voucher, which can be used to buy any future cruise costing up to 125 percent of the original fare. Additionally, passengers booked on any 2020 voyage can now transfer their booking to any other cruise even if their sailing has not been cancelled. Passengers only have to advise Fred. Olsen at least two weeks prior to departure as part of the line's recently-introduced "Plain Sailing Guarantee."

Any passengers who are booked onto cancelled sailings will be contacted by Fred. Olsen, with at least 30 days' notice prior to the planned departure date.

The ocean fleet -- Balmoral, Braemar, Boudicca and Black Watch -- is currently in Scotland’s Firth of Forth.