WASHINGTON (AFP) - Homicides fell sharply in many leading United States (US) cities in 2013, plummeting by as much as 20 per cent, official data showed on Wednesday.

America's biggest metropolises, such as New York, Chicago and Los Angeles, which witnessed sky-high murder rates in the 1990s, saw a continuation of the downward trend of recent years.

New York recorded 333 homicides through Dec 29, 2013, according to city figures, 84 fewer than one year earlier.

There were also significantly fewer homicides in Los Angeles, the second largest US city, with a 17 per cent decline last year.

President Barack Obama's adopted hometown of Chicago, America's third biggest city in population, also had a notable drop in murders.

Chicago had been struggling to stem an epidemic of homicides, after gang violence pushed the murder toll there to 501 in 2012.

Crime reports through Dec 27, 2013, showed 407 homicides, a nearly 20 per cent drop.

Washington was an exception to the national trend, however, with 17 per cent more murders committed last year than in 2012.

Officials in the US capital explained that the rise was in part a statistical anomaly, since the previous year, 2012, registered an unusually low 88 killings.

They also pointed to the September 2013 murderous rampage by a gunman at Washington's Navy Yard who killed 12 people - a single act of violence which they said skewed the city's annual homicide figures.