Emergency services were called to the park, in Hamerton Road, shortly after 11am and visitors to the venue were swiftly evacuated.Both the Magpas air ambulance and East of England Ambulance Service were called to attend the scene but, in a statement released by Cambridgeshire police, it was confirmed that a female keeper had died, although the circumstances remain unclear.A spokesman said: A tiger had entered an enclosure with a keeper. Sadly the female keeper died at the scene. At no time did the animal escape from the enclosure.The spokesman added that the incident is not being treated as suspicious. A spokesman for Magpas added: At 11:34am today, the Magpas enhanced medical team were called to a very serious incident.An East of England Ambulance Service paramedic crew and two rapid response vehicles were also in attendance, alongside the police.A statement attributed to a zoo spokesman said: This appears to have been a freak accident. A full investigation is currently under way and we hope that more details can be announced as soon as we are able.At no point during the incident did any animals escape their enclosures, and at no point was public safety affected in any way.All our thoughts and our sympathies are with our colleagues friends and families at this dreadful time.The statement added that the park would be closed tomorrow (May 30).Eyewitness Jeff Knott, from Cambridgeshire, said staff had been a real credit to the zoo during the evacuation.The 32-year-old told the Press Association: We had been in the zoo since about 10.30am and heard/seen nothing until asked to leave about 11.45am.Staff were very calm and professional. All visitors around us were leaving in a very calm manner no running, shouting or anything similar.Antonia Brickell from Magpas air ambulance denied reports that visitors had been running in terror, adding: The visitors were safely evacuated from the zoo.