Wales full-back Liam Williams is an injury doubt for Sunday's World Cup semi-final against South Africa, according to reports.

Williams is reported to have sustained an ankle problem during training ahead of the showdown with the Springboks in Yokohama.

Wales are set to announce their team for the World Cup semi-final on Friday at 03:30 BST

Williams, with 62 international caps as well as representing the British and Irish Lions, has been one of the key men in Warren Gatland's squad.

Should the 28-year-old be ruled out of Sunday's game, then Scarlets full-back Leigh Halfpenny is likely to replace him.

Apart from back-row forward Josh Navidi, who will miss the remainder of the tournament due to a hamstring injury, Wales had been hoping for a clean bill of health.

Centre Jonathan Davies missed the quarter-final victory over France because of a knee problem suffered in Wales' Pool D victory over Fiji earlier this month, but has resumed training.