Three dogs have died and three more required treatment after being poisoned in a London park, police said.

Two bull lurchers and a springer spaniel died after ingesting poison in or near Fryent Country Park in Brent, north-west London.

The Metropolitan Police described the incidents as "nasty" while the RSPCA warned that the dogs would have experienced "a great deal of suffering".

The first poisoning occurred on January 21 when a dog died after eating blue tablets near a lay-by on Fryent Way, inside the park.

On Thursday three dogs ate poisoned meat that was left on a grass verge in Salmon Street, just outside the southern entrance to the park. One of the dogs died while two others survived after receiving treatment from vets.

The following day two more dogs ate poisoned meat that had been placed in the undergrowth on the same street. One died and the other survived.

Simon Osborne, chief inspector for the RSPCA, said: "We are very concerned to hear these reports. Poisoning is a cruel and inhumane way for an animal to die and one which would have caused these dogs a great deal of suffering.

"The RSPCA has offered the police any support they need in dealing with these incidents and urges anyone with any information to come forward."

A Natural England spokesman said: "This is a very serious incident and clearly very distressing for dog owners in the area. We will be assisting the Met, under the Wildlife Incident Investigation Scheme, to determine whether pesticides are involved."

Sergeant Peter Rowntree from the Metropolitan Police said: "This is such a nasty, cruel act which has killed three beloved dogs and endangered all domestic pets and wild animals, in such close proximity to a country park.

"Family pets, wildlife and the amenities of a country park are factors that enhance the quality of people's lives. The owners and families of the dogs affected have suffered acute distress. This is not simple, ignorant mischief, but criminal activity and the persons found to be responsible will be prosecuted."

Anyone with information is asked to contact Brent police on 020 8733 3804.