The survey of 56 cities by the Police Executive Research Forum found that, overall, the number of homicides was up nearly 3% compared with 2005, while robberies were up 6.5% and assaults involving guns rose 1.3%. Aggravated assaults, which typically involve any type of weapon, declined 2.2%.

The new numbers add to evidence that violent crime has been ticking upward for two years after more than a decade of declines. During the past two years, the forum's report says, overall homicides in the surveyed cities were up 10%, robberies rose 12% and assaults involving firearms were up nearly 10%.

"We're seeing a volatility in violent crime that we haven't seen in the past 10 years," says Chuck Wexler, executive director of the forum. "At the local level, people are paying attention to this. At the national level, it's taken more time to connect the dots. We believe this data demonstrates a significant national problem."

The forum began its surveys of violent crime in 2005, when the FBI recorded the first nationwide increases in rates of violent offenses in more than 10 years. The jumps in violence, the group says, warrant the reconstitution of the Clinton administration's program that provided funding for 100,000 additional police officers across the nation.

Last month, the Bush administration proposed a $200 million grant program to help police agencies pay for overtime, equipment and other costs of responding to violent crime.

Boston Police Commissioner Ed Davis says the program is a start, but more needs to be done. "People are dying, and they are dying in significant numbers," Davis says. "We don't have the resources to deal with these problems."

In Boston, he says, gangs and the increasing use of guns in crimes have contributed to a 23% jump in homicides during the past two years.

Among the cities recording the largest increases in violent crime in the survey:

•Orlando. Homicides jumped from 22 in 2005 to 49 in 2006, a 123% increase. Robberies rose 27% last year.

•Atlanta. Homicides rose from 89 in 2005 to 107 last year, a rise of 20%.

•Miami— There were 77 homicides in 2006, a 43% jump from the 54 reported in 2005.

Several cities reported slight declines in violent crime.

Milwaukee, Nashville and Norfolk, Va., for example, reversed double-digit percentage increases in homicides recorded in 2005 with double-digit declines last year. In Washington, D.C., where the number of homicides had dropped slightly in 2005, the number of slayings fell 13% last year, to 169.