A police officer was left with "serious bite injuries" after being attacked by a dog believed to be an XL bully.
The Leicestershire Police officer was called to a property in Ibstock, near Coalville, in search of a wanted man at around 4.40pm on Thursday, the force said.
He and another male officer attended the call and were both bitten by the dog, with the first taken to hospital for "serious bite injuries" to his upper leg and the second treated for a cut to his finger.
The dog has been seized and placed in secure kennels pending an investigation.
A Leicestershire Police spokesman said: "Although the dog has not been further examined, it is believed to be an XL bully breed. This dog and a second dog, a pit bull type breed, were seized from the address and remain in secure kennels.
"Enquiries are ongoing into the incident. There have been no arrests."
The breed, which has been developed from the American pit bull terrier, is not officially categorised in the UK.
Prime Minister Rishi Sunak has vowed to ban them, but dog experts argue the move is problematic.
Campaigners say that after several bite incidents, including a fatal one that killed a 52-year-old man in Staffordshire in September, any attempts to ban them could also outlaw other similar breeds.
Police shot dead an XL bully in the grounds of a Norfolk primary school earlier this month after it attacked a woman in her 60s.
And in September an 11-year-old girl was left with serious injuries as a result of a similar attack.