Gun crime in London rose by 4% last year, but the overall number of crimes dropped for the fifth year in a row, the Metropolitan Police said.
Gun offences have risen slightly, despite an overall drop in crime
Overall crime fell by 6.1% compared to 2006, with the number of knife crimes down by 13% and the murder figures falling by nearly 7%.
Serious crimes such as murder and rape fell sharply in the last five years.
Mayor Ken Livingstone said: "There is a resistant problem of gang-related knife and gun crime involving young people."
The Met also expressed its concern at the number of teenagers murdered in 2007 - 26 compared to 17 in 2006.
Deputy commissioner Paul Stephenson said: "We are very concerned about the rise in the number of teenage murders and tackling that is seen as a priority."
He tried to play down links between the jump in murders and the alleged rise in gang culture and said: "We have got to avoid getting involved in a dialogue which gives misplaced kudos to gangs.
"We cannot let this myth prevail that these murders suggest a risk of all-out gang warfare.
"While there is an issue of gangs, the real issue is youth crime and sometimes they overlap but the idea that gangs are behind the rise in murders is misplaced."
According to Metropolitan police figures, the number of murders fell from 222 in 2003, to 194 in 2004, to 178 in 2005, to 172 in 2006, and down to 160 in 2007.
The number of rapes fell 25% since a peak in 2002.
Despite the slight rise in 2007, the overall amount of gun crime fell 22% compared to 2002, police said.
Mr Livingstone said: "This is good news for Londoners and shows the improvement in policing in the capital.
"By increasing police numbers and putting police back on the beat, crime is falling steadily very year.
"The average decline in crime per year over the last three years is 5.5% a year. Murder has fallen 6% a year.
"We now have more police in London than at other time in history."
The mayor said the majority of youth crime was caused by boredom, so an extra £79m has been budgeted for youth projects in London boroughs this year.
The overall number of youth crimes in 2007 fell slightly compared to 2006 - from 1,428 to 1,392, a fall of 2.5%.
Robberies fell from 46,204 to 39,364 in 2007, a drop of 14.8%.