LONDON - London police chiefs said they were launching a widespread crackdown on youths carrying knives after admitting that a recent spate of murders showed current initiatives were not stopping the problem.

Assistant Commissioner Tim Godwin, head of territorial policing in the capital, said officers would be deployed across areas blighted by stabbings to stop and search teenagers suspected of carrying weapons.

The announcement comes after a series of murders and stabbings in the last few days.

On Monday, a man was knifed to death on Oxford Street, one of the busiest shopping areas in the country, and 16-year-old Jimmy Mizen died after his throat was slashed after declining to become involved in a fight with a man in a bakery on Saturday.

"We do now have to do something significant in relation to tackling the issues of knives being carried in our communities," Godwin told reporters.

"We really, really, have to do something about carrying weapons on the streets of London. This is the time to say enough is enough."

He said police would use "fairly invasive" powers allowing officers to stop and search people in an area where intelligence indicated young people would be carrying knives and weapons.

The crackdown would begin in an area which had seen the most stabbings before being rolled out to 10 other boroughs across the capital.

Godwin said the action was necessary because youth fatalities and knife crime were their most "serious concern" and had been "resistant to our activities to date".

Community bodies often complain that stop and search is a blunt instrument which unfairly targets certain groups, particularly black youths.

Godwin acknowledged that some people could take issue with measures but added that those living in many neighbourhoods, including teenagers, wanted the police to take action to protect them.

He promised that the searches would be carried out sensitively, professionally and "with a smile".