Republic of Ireland fans face a scramble for tickets for October's qualifier with Wales.
The Football Association of Wales have confirmed that the 38,000-seater Cardiff City Stadium, and not the 74,500-capacity Principality Stadium, will host the World Cup qualifier.
Wales need only provide the minimum of 5% of seats for travelling support.
That means Ireland could have as few as 1,664 fans in the stadium on October 9.
Ireland are currently on 12 points, alongside leaders Serbia in Group D. Wales and Austria both have eight points, with four games to go.