The UEFA official said: 'It is nice pictures. We are not 100 per cent against it but we are cautious.'
The 3-1 quarter-final victory over Belgium in Lille last week was the biggest win in Welsh football history, but that will soon be eclipsed should Chris Coleman's side beat Portugal in Lyon on Wednesday to reach their first ever international final.
The magnitude of Wales's win over much-fancied Belgium was reflected in the players' joyous celebrations on the pitch afterwards.
Captain Ashley Williams was seen with his two children in his arms, while defender Neil Taylor and goalscoring hero Hal Robson-Kanu were also seem celebrating with their families on the pitch. Star man Gareth Bale hugged his daughter, Alba, on the field after the win over Northern Ireland in the last-16.
Wales will have to beat Cristiano Ronaldo's side without key men Aaron Ranmsey and Ben Davies, with both men suspended for the semi-final after picking up two yellow cards in the tournament.
Leicester midfielder Andy King is expected to be brought in to replace the impressive Ramsey, while West Ham defender James Collins should get the nod to take Davies's place as one of the three centre backs.
Fulham left back Jazz Richards is, however, under consideration to fill in for Davies in what would be his first start in the competition.
-Daily Mail