Police have vowed to 'leave no stone unturned' in the hunt for knifemen after two boys, aged 15 and 16, were stabbed to death in south Bristol on Saturday night.

Police scrambled to the scene 'within minutes' of a call to an address on Ilminster Avenue, in Knowle West, at around 11.20 pm yesterday where the two teenagers were discovered.

Police carried out first aid at the scene before the two boys were rushed to hospital by ambulance after sustaining fatal stab wounds.

Two arrests have already been made – a 44-year-old man and a 15-year-old boy, who remain in police custody. A vehicle was also seized as police continued their inquiries.

Avon and Somerset Police confirmed that the boys had been attacked by several people who fled from the scene in a car.

The teenagers sadly died at Southmead Hospital and Bristol Royal Hospital for Children in the early hours of Sunday morning, with the boys' families by their side.

Police have launched a murder investigation, which is being led by the force's Major Crime Investigation Team.

A heavy police presence remains at the scene with house-to-house enquiries underway and CCTV and doorbell footage being gathered by investigating officers.

Forensic officers could also be seen combing the street this afternoon.

Police say it is not yet clear at this stage what the motive was behind the attack or if the attackers and victims were known to each other.

Neither boy has yet been identified and post-mortem examinations will be carried out in due course.

In a press conference on Ilminster Avenue this afternoon, Bristol Commander Superintendent Mark Runacers said that boys' families had been made aware of the two arrests, and are being supported by specially trained family liaison officers.

He told reporters: 'The boys' families were with them at the hospital and our thoughts are with them as they process these awful events'.

He added: 'I'd like to reassure people that we will leave no stone unturned in our efforts to catch those responsible for this reprehensible attack and provide answers to the victims' families.

'We are in the early stages of our inquiry but we have already identified several witnesses who we will be taking statements from'.

Further suspects are 'being sought' amongst the group believed to be responsible, he said.

He urged anyone who has any information to come forward to either the police or Crimestoppers anonymously 'as soon as possible'.

Detectives are particularly keen to speak with passengers on a double-decker bus which was on Ilminster Avenue at the time of the attack and remains at the scene.

It's not believed anyone involved in the incident was on or got off the bus, Supt Runacres said.

A mobile police station has been setup near the scene where a large cordon remains in place on Ilminster Avenue, between Newquay Road and Tavistock Road.

CCTV cameras are dotted around the area - including one at the junction between Newquay Road and Ilminster Avenue.