A report from noted how United were entitled to as many as 9,000 tickets. However, Arsenal have dished out only 5,000 amid concerns about supporter safety at the Emirates Stadium.
However, they will receive only 5,233 tickets after Arsenal reduced the allocation on the recommendation of their safety advisory group over concerns that away fans would stand in the upper tier.
United challenged the decision but it has been ratified by the FA, who granted Arsenal dispensation to cut the number of tickets available to their opponents.
United had no option but to accept the decision because it is on safety grounds, and are also aware of the need to allocate tickets through their ballot system as soon as possible so fans can make travel plans for the game in nine days’ time.
It is not the first time that Arsenal have cut the ticket allocation for a Premier League rival for a cup tie at the Emirates, and there are concerns that they did not follow the rules by seeking dispensation from the FA before originally reducing United’s share.
Fans groups from both clubs criticised the decision. A spokesman for Manchester United Supporters Trust said: ‘For Arsenal to offer little over half the proper allocation is a joke.
‘And to say away fans cannot be in an upper tier, where they are at many league grounds, is ridiculous.
‘What’s more, this needs to be sorted now. The game is just 10 days away and at present United are unable to sell tickets to their fans. 
Supporters need to make arrangements for a fixture which has already been shifted to an inconvenient Friday night kick-off time.
‘We need to keep the FA Cup special, and that means making Arsenal stick to the full away fan allocation.’ The Arsenal Supporters Trust also called for United to be given the full allocation, mindful that they will want the same if the tie goes to a replay at Old Trafford.
‘Set at 15 per cent in rules. Creates great atmosphere and differentiation to Premier League. So frustrating to see this under threat at Emirates for MUFC cup tie.
‘Should there be a replay we would want 15 per cent of Old Trafford to support our team. The continual attack on rights of all away fans does nothing to help football as a live match experience.’