Image caption Mayor Bloomberg and police chief Raymond Kelly say stop-and-frisk tactics led to fewer murders

The number of murders in New York City is expected to hit a record low this year, as officials credited police efforts in reducing crime.

So far, there have been 414 homicides in the city, down 19% from 2011 and the fewest since reliable records began in 1963.

Mayor Michael Bloomberg said the number showed that "the safest big city in America is safer".

Meanwhile, Chicago has hit 500 murders for the year.

The US' third largest city has seen a wave of gang violence in the past year, including one weekend day on which six people died.

'Stop-and-frisk'

Mr Bloomberg and New York Police Commissioner Raymond Kelly announced the numbers during a police academy graduation on Friday.

The 2012 murder rate was less than a fifth of the city's record of 2,245 homicides in 1990.

The drop in the murder rate is "a testament to the hard work and determination of the men and women who put their lives on the line for us every day, "Mr Bloomberg said. "And it also reflects our commitment to doing everything possible to stop gun violence."

When people ask me, 'What's different about Chicago?' that's one of the things I tell them. We have a proliferation of illegal firearms Garry McCarthy, Chicago police superintendent

In a statement, Mr Kelly attributed the decline to the increasing use of stop-and-frisk, a controversial tactic where police can stop and search people on the street they consider suspicious.

"We're preventing crimes before someone is killed and before someone else has to go to prison for murder or other serious crimes," he said.

Civil rights groups and some local politicians have criticised the practice, saying that most people stopped turn out to be innocent, and that it unfairly targets black and Latino men.

Other crimes like rapes, robberies, assaults and burglaries were up slightly in the city, while grand larceny went up by 9%, due to increased thefts of electronic devices.

Gangs and guns

Chicago recorded its 500th murder on Friday.

While the city's murder rate is now higher than New York City, Chicago has only about one-third of New York's population.

Most of the violence has been in Chicago's troubled south and west sides, but there also have been a handful of incidents in the downtown area.

Police Superintendent Garry McCarthy and other officials blame the death toll on a splintering of the city's traditional gangs as well as a large number of illegal guns available in the city.

"In the first six months of the year, we seized three guns for every gun seized in Los Angeles and nine guns for every gun confiscated by the New York Police Department," Mr McCarthy said.

"When people ask me, 'What's different about Chicago?' that's one of the things I tell them. We have a proliferation of illegal firearms," he said.

Illinois does not ban assault weapons and the high-capacity magazines as do New York and California.

The city's homicides were 80% gang-related, and 80% of the victims were black, although only 33% of the city's population is black.