Two youths have been arrested on suspicion of murder after a teenager was stabbed to death in east London.
The 15-year-old boy was found by police on Whitwell Road, Plaistow, at about 2300 GMT on Saturday. A large group of youths ran off as the officers arrived.
The boy was taken to hospital where he died soon afterwards. Two youths thought to be aged about 17 were held.
The Met Police said the 15-year-old was the first teenager to have met a violent death in London in 2009.
Last year, 28 teenagers were killed in violent incidents in the city.
A fingertip search of the scene is being carried out and several police officers are examining the area for evidence and speaking to residents.
Police have cordoned off the area between the junction of Barking Road and Balaam Street up to the Foresters Arms Pub
in Abbey Street.
A local man, who did not want to be identified, said his nephew was a friend of the victim, and that both of them were "threatened".
He said: "All these kids have got to put down their knives. He [the victim] was not a knife carrier. He just went to a party to meet his mates. But his mates weren't there and a group of lads came and he got stabbed."
A 15-year-old girl, who did not want to be named, said the stabbing followed a row at a fund-raising event at a church hall attended by about 100 people.
The party was brought to an end at 2230 GMT after a fight broke out, she said.
She said: "I saw pushing and arms swinging around. Then the bouncers came in and said the party has been knocked off.
"I was expecting a fight but I wasn't expecting anyone to get stabbed. There is always a fight, that is why I left early. I rang my friend and she said someone had got stabbed."
Another local resident said: "There were between 50 to 100 kids and there was a lot of screaming and shouting. I was watching out of my window and they looked like they had all come from somewhere together."
In a separate attack, a 14-year-old boy was shot in the head in Tulse Hill, south London.
Police said his injuries were not thought to be life-threatening.
A 16-year-old boy was also shot but suffered only a grazed arm. THE BBC