The Royal Navy aircraft carrier HMS Prince of Wales has broken down shortly after embarking for exercises in the US.
The carrier left from Portsmouth Naval Base on Saturday before an “emerging mechanical issue” occurred.
The Royal Navy has said HMS Prince of Wales remains in the South Coast Exercise Area.
The vessel’s departure was planned for Friday but had been delayed because of a technical issue.
The Royal Navy was not able to offer any further details or confirm if the earlier technical issue was related to the mechanical problem.
Specialist website Navy Lookout has reported that the issue was caused by damage to the starboard propeller shaft although the MoD has not confirmed or commented on this.
The website says a photograph of the carrier leaving Portsmouth shows only a wake on the port side suggesting a problem with the other propeller shaft.
It states that, unless the problem can be resolved at sea enabling the warship to continue its journey to the US, it might need to go into dry dock at Rosyth in Scotland early, ahead of a planned inspection in 2023.
The Nato flagship is sailing to undertake training exercises with the US Navy as well as the Royal Canadian Navy and United States Marine Corps.
The 65,000-tonne warship, built at Rosyth at a cost of £3bn, had a colourful send-off on Saturday as it passed thousands of revellers at the Victorious Festival on Southsea Common.