Both violent and property crimes declined in 2007 from the previous year, the FBI reported Monday.

In preliminary figures for crimes reported to police, the bureau said the number of violent crimes declined by 1.4 percent from 2006, reversing two years of rising violent crime numbers. Violent crime had climbed 1.9 percent in 2006 and 2.3 percent in 2005, alarming federal and local officials.

Violent crime in Utah's second-largest city — West Valley City — however, jumped more than 23.5 percent between 2006 and 2007, according to the FBI report.

Of the state's three largest cities, West Valley City was the only one to see an overall increase in murders, rapes, robberies and aggravated assaults, according to the annual Uniform Crime Report. West Valley police handled 479 violent crimes in 2006 and 592 the following year.

During the same time, Provo's violent crimes dropped from 181 to 166, while violent crimes decreased by less than 1 percent in Salt Lake City — from 1,504 to 1,493.

In Salt Lake City, a law enforcement official said a renewed focus on community policing appeared to be showing early results, but he cautioned that numbers don't tell the entire story.

"Any time there's a drastic change, either higher or lower, it helps us understand what programs may be working well, or maybe aren't working well," said Salt Lake police detective Jeff Bedard. "The numbers help us in a broader sense of where trends are going, but we try not to get lost in that."

As a snapshot, Bedard said such numbers can also be deceiving. Salt Lake's murder rate doubled from eight to 16. That increase can be blamed, in part, on the Trolley Square shootings that left five people dead, Bedard said.

Property crimes in Utah's three largest cities increased 4 percent, according to the federal report. In Salt Lake City, crimes such as burglary and theft dropped by about 1.7 percent, while Provo and West Valley City saw increases of 11 and 16 percent, respectively.

Property crimes across the country were down 2.1 percent last year, the largest drop in the last four years.

The largest declines were in vehicle theft, down 8.9 percent and in rape, down 4.3 percent and murder, down 2.7 percent.

The crime trends were not uniform. Murders, for instance, were down in cities of more than 250,000, including an enormous 9.8 percent drop in cities of more than a million residents. But murders rose in some small cities — up 3.7 percent in cities of 50,000 to 100,000, up 1.9 percent in cities of 100,000 to 250,000, and up 1.8 percent in cities under 10,000. Historically, national murder trends have begun in the largest cities and moved over several years to smaller ones.

Because the FBI preliminary figures do not contain the detailed age, race and gender breakdowns available in the final report later in the year, they may unintentionally mask a growing murder rate among black male teenagers and young adults, particularly with guns, said James Alan Fox, professor of criminal justice at Northeastern University.

"We shouldn't be fooled into thinking our problems are over," Fox said. He pointed out that from 2002 to 2006 the rate of murder committed by black male teens rose 52 percent.

"Violence is down among whites of all ages and both genders; it's up among black males, not black females," Fox said. "When you blend all the national numbers together you fail to see this divergence. There are many more whites in the population, so their decline can dwarf the increase among young black males."

Fox said black males are "feeling the impact of the economic decline and an increase in gangs and illegal gun markets. Gangs and youth crime are a growing problem despite these rosy statistics."

Professor Alfred Blumstein of Carnegie Mellon University said overall national crime figures have been fairly stable with only small fluctuations since 2000. Gangs have re-emerged in various inner-city neighborhoods in recent years, Blumstein added, but they have not been the highly structured, almost-corporate entities like the Bloods and the Crips that spread out from Los Angeles in the 1970s.

The biggest changes in this report seem driven more by individual city variations than by regional or national trends, Blumstein said. The big murder decline in the biggest cities and in overall violent crime in the Northeast is substantially attributable to an enormous 17 percent drop in murders in New York City alone, from 596 in 2006 to 496 in 2007, he said.

"When you see a crime spike in a city, it's very often attributable to young black males attacking other young black males," Blumstein said. "The duration depends on how fast the city reacts, and the big cities have more resources and more sophistication about how to respond."

In New York, police attribute the decline in murders to their Operation Impact, which floods high crime areas with officers, including some fresh from the academy. New York Mayor Michael Bloomberg also credited "efforts to keep illegal guns out of the hands of criminals."

Of 21 cities with more than 100 murders a year a few years ago, 13 saw murders rise in this report and 8 recorded declines, Blumstein said.

FBI spokesman Richard Kolko said, "One preliminary report does not make a trend, but it's going the way we want it to go." Kolko cautioned against attributing significance to any shift that hasn't lasted at least two years.

Justice Department spokesman Peter Carr called the report "very encouraging" though he noted the final report could alter the figures.

"The report suggests that violent crime is decreasing and remains near historic low levels, which is a credit to increased cooperation among federal, state and local law enforcement," Carr said. "Some communities, however, continue to face localized violent crime challenges."

Carr said the Justice Department is "committed to providing targeted assistance wherever needed."

But Sen. Joseph Biden, D-Del., who chairs a Senate subcommittee on crime, said, "The decreases announced today are modest. There are nearly 1.4 million violent crimes and over 17,000 murders in America every year, and that's simply too many. ... The Bush administration has repeatedly ignored the needs of law enforcement, slashing overall funding for state and local law enforcement by billions."

According to the preliminary report, other violent crimes tracked by FBI statistics — robbery and aggravated assault — were both down 1.2 percent.

The other property crimes also declined, larceny-theft by 1.2 percent and burglary by 0.8 percent.

Arson dropped 7.0 percent, but it is not included in overall FBI property crime figures, because fewer localities report on the crime.

Violent crimes dropped most in the Northeast, down 5.4 percent with 1.7 percent declines in both the Midwest and West. But they rose 0.7 percent in the South.

Blumstein said murder figures varied widely among Southern cities, with the biggest increase in New Orleans, up 29 percent from 162 to 209. Atlanta saw a 17 percent rise; Jacksonville, Fla., 12 percent. But murders dropped 18 percent in Birmingham, Ala., and 13 percent in Memphis, Tenn.

Property crimes also rose only in the South, where they were up 1.1 percent. The West recorded a 4.7 percent decline in property crimes, followed by the Midwest, down 3.6 percent and the Northeast, down 2.9 percent.

The FBI's preliminary crime report each year gives percentage changes rather than national totals for each crime because not every jurisdiction has filed its reports yet.