Police crime scene tape in New York. (Stephen Chernin/Getty Images)

The number of violent crimes committed across the country was up in the first half of 2015 compared with the same period a year earlier, with increases seen across the country and spanning different types of crimes, federal authorities said Tuesday.

The numbers of murders, rapes, assaults and robberies were all up over the first six months of 2015. Overall violent crime was up 1.7 percent, an increase that followed two consecutive years of declines, according to the FBI.

These figures come after a year that saw murder rates go up in cities nationwide, sparking a series of tense media reports.

The numbers are among the preliminary figures released by the FBI as part of its Uniform Crime Reporting program, a national storehouse relying on the voluntary participation of more than 18,000 law enforcement agencies. The numbers released Tuesday came from more than 12,000 agencies submitting comparable data for the first six months of 2014 and 2015.

[Americans always think crime is on the rise, aren’t so worried about being the victims of crime]

Between January and June 2015, the number of murders was up 6.2 percent, with the biggest jumps seen in the country’s smallest and largest areas. Murders were up 17 percent in areas with fewer than 10,000 residents, while murders were up 12.4 percent in places with between half a million and a million residents and up 10.8 percent in places with more than 1 million residents.

The Census Bureau has said that small places — incorporated areas with fewer than 10,000 people — account for about 9.1 percent of the total U.S. population.

Most local law enforcement agencies represent smaller areas, even though they combine to employ fewer officers than larger areas, Justice Department data shows.

Seven out of 10 local law enforcement agencies serve areas with fewer than 10,000 residents, employing about an eighth of all full-time local police officers. By comparison, only 3 percent of local police departments serve populations of at least 100,000 people, and they employ about half of local police officers.

[What police chiefs and elected officials say amid a spike in murders]

The FBI found that violent crime increased in most regions of the country — with one notable exception. It actually fell by 3.2 percent in the Northeast, even as it ticked up by 5.6 percent in the West, 1.6 percent in the South and 1.4 percent in the Midwest.

Rapes were up using the FBI’s newer definition (which includes more forms of sexual assault) as well as going by the older definition, while aggravated assaults and robberies both ticked up.

Property crimes including burglaries and larcenies fell over the first half of last year, with an increase in only one category: Car thefts, which were up 1 percent.

The FBI had said last fall that violent crime fell in 2014, part of an overall drop in violent crimes seen in recent years.

Homicides and shootings were increasing last year in a number of major metropolitan areas, with dozens of big cities reporting upticks in both categories, according to the Major Cities Chiefs Association. While this comes after a lengthy period of falling crime rates, criminologists said it was not clear what was happening and counseled patience.

The overall violent crime rate has fallen significantly over the last two decades, falling from 79.8 victimizations per 1,000 people in 1993 to 20.1 per 1,000 in 2014, according to Justice Department figures. Last October, the Pew Research Center released an analysis of death certificate data and said that gun homicide rates had dropped significantly since the early 1990s.

In the country’s biggest cities, the murder rate is expected to be higher in 2015 than 2014, even though the overall rate of murders remains relatively low, the Brennan Center for Justice, a law and policy institute in New York, concluded in a recent analysis.

“Because the underlying rate of murders is already so low, a relatively small increase in the numbers can result in a large percentage increase,” the report noted. Its authors added: “One year’s increase does not necessarily portend a coming wave of violent crime.”

The number of murders increased significantly in Washington (up 54.3 percent last year over 2014) and Baltimore, with increases also seen from Denver to Chicago. The Brennan Center last month released updated figures and noted that there were declines in cities like Boston and Memphis.

(It is worth noting here that a city’s homicide count, which is often used as a measure of violence, is not a precise tool.)

Still, Americans are usually pretty sure that crime is going up in the United States. Polls dating back a quarter of a century show that most Americans consistently think that crime is up, not down, across the country, even when crime is falling.

Related:

An increase in violent crime sparked concerns across the country

What law enforcement officials say behind closed doors

FBI director: We will collect and publish more info about fatal police shootings

The Watch: There’s no evidence of a ‘new nationwide crime wave’

I went looking for the uptick in murders in U.S. cities. Here’s what I found.