The U.S. violent-crime rate continued to climb in the first half of 2006, and federal officials placed some of the blame on rising use of methamphetamine, Reuters reported Dec. 18.

Violent crime -- including offenses like murder, rape and robbery -- rose 3.7 percent in the first six months of 2006, the FBI reported, led by a 9.7 percent rise in robberies. In 2005, the violent-crime rate jumped 2.5 percent, the biggest increase in 15 years.

Officials from the U.S. Justice Department said that factors like rising use of methamphetamine, increased gang violence, and simple demographics may be behind the trend, although a detailed study on root causes is still underway. They denied that a shift in resources away from basic law enforcement to antiterrorism efforts was behind the increase.