It is believed the attacks may have been carried out by the same thugs but are not being linked to protests over the recent hunting ban, the RSPCA said.

The first animal was found in the city's Cardigan Street, on Monday. It had been skinned and had its tail and paws cut off.

The second was found in the city centre on Tuesday in a home-made snare.

RSPCA inspectors and Northumbria Police have condemned the dismembering of the animals as "barbaric" and have joined forces to find the culprits.

'Cruel and vicious'

A spokesman for the RSPCA said: "There is nothing to suggest they are linked to the fox hunting ban and Sunderland is not an area renowned for hunting."

Although foxes are not protected, it is illegal under the Wild Mammals Act 1996 to mutilate them intentionally.

Anyone found guilty of the offence could face a prison term of up to six months and a fine of up to �5,000.

RSPCA Inspector Michelle Charlton said: "The fox was found in the area that another was discovered, skinned and mutilated.

"On initial examination it appears to have been strangled by the snare.

"We would urge anyone with information about who is targeting Sunderland's wildlife in such a cruel and vicious manner to call either the police, or us."