The FA are looking into reports of what Newcastle fans described as a 'crush' when entering Hillsborough.
Images from the Leppings Lane end, where 97 Liverpool supporters were fatally injured in 1989, show Newcastle fans packed together around one entrance to the seating area.
The club's Supporters' Trust has asked witnesses to contact them.
One Twitter user, Barry, wrote: 'I was in the centre of the lower tier and it was ridiculously crowded 10 minutes before kick-off. The stairwell filled with fans and when we arrived we asked stewards to point us in the right direction.