LONDON - TWO French students found stabbed to death in a burning London flat had been subjected to a 'frenzied, brutal and horrific attack', police said yesterday.

The bound and battered bodies of Laurent Bonomo and Gabriel Ferez, both 23, were found in the ground-floor studio flat in New Cross, south-east London, on Sunday when emergency services were called after the fire broke out. An explosion was also reported.

Police said they were at a loss to explain the killings, which a senior detective described as the most violent he had ever seen.

Mr Bonomo was stabbed nearly 200 times while Mr Ferez suffered around 50 wounds during a prolonged ordeal, said unidentified police sources quoted by the domestic Press Association news agency.

Detective Chief Inspector Mick Duthie, who is leading the investigation, said the two were dead before the fire took hold. He added that they had been knifed in the head, neck, torso and back.

'The extent of the injuries is horrific,' he said, urging witnesses to come forward.

'I have never seen injuries like this throughout my career.

'We are here today because I don't know why these boys were killed or who killed them.'

Police are looking at the possibility that the students were the victims of mistaken identity.

Mr Duthie said the two students - biochemists from a university in Clermont-Ferrand, central France - were on a short exchange programme at the Imperial College.

They were due to return home at the end of this month.

At the scene of the crime, police guarded the front door of the 1980s flat in a leafy cul-de-sac.

A tarpaulin covered a broken window. When the wind lifted it up, several broken windows and a charred sofa could be seen inside.

'A Spanish woman, who lives in the block, told me she had seen two men banging on their window' from the outside, said Ms Christina Ramires, 32, a Brazilian journalist who lives on the ground floor of the building.

'The Spanish woman said they were wearing hats...then she heard a very strong sound, a bomb.'

There is growing concern about knife crime and the gang culture in London, which Mayor Boris Johnson and Metropolitan Police chief Ian Blair have vowed to tackle.

Police and the Home Office say overall knife crime in London is falling.

But 17 teenagers have been knifed to death so far this year - already more than half the total number for the last 12 months.

Lawyer Cherie Booth, wife of former prime minister Tony Blair, told a parliamentary committee on Tuesday that knife crime was more prevalent than figures suggested, and blades were being carried at a younger age.

AGENCE FRANCE-PRESSE, REUTERS