A tannoy announcement in the centre shortly before 3pm said 'there has been an incident please leave and do not re-enter'.
Scott Eaglen, a shopper at the centre, said: "I arrived at the White Rose around half an hour ago.
"As we were just walking in we heard the fire alarm (I assume) going off and people rushing out, including staff and members of the public.
"There was no real panic, until the tannoy came on stating ‘There has been an incident on site, do not, we repeat DO NOT enter the premises'.
"At that point people just started leaving."
West Yorkshire Police have been contacted.
It is believed some members of the public and staff are being allowed to go back inside the centre shortly after 3.30pm.
More to follow.