WASHINGTON (Reuters) - The United States, which has the most prisoners of any country in the world, last year recorded the largest increase in the number of people in prisons and jails since 2000, the Justice Department reported on Wednesday.

A October 25, 2004 file photo shows a guard at San Quentin prison checking doors of cells housing death row inmates inside San Quentin prison. The United States, which has the most prisoners of any country in the world, last year recorded the largest increase in the number of people in prisons and jails since 2000, the Justice Department reported on Wednesday. REUTERS/Clay McLachlan/files

It said the nation’s prison and jail populations increased by more than 62,000 inmates, or 2.8 percent, to about 2,245,000 inmates in the 12-month period that ended on June 30, 2006. It was the biggest jump in numbers and percentage change in six years.

Criminal justice experts have attributed the record U.S. prison population to tough sentencing laws, record numbers of drug offenders and high crimes rates.

State or federal prisons held two-thirds of the nation’s incarcerated population while local jails held the rest, according to the report by the department’s Bureau of Justice Statistics.

The number of inmates in state prisons rose by 3 percent, the report said. That growth mainly reflected rising prison admissions, which have been going up faster than the number of released prisoners. Also, more parole violators have returned to prison, the report said.

Forty-two states and the federal system all had more inmates in June last year than the previous year. The number of jail inmates increased by 2.5 percent during the same 12-month period, the report said.

The report on U.S. prison numbers is issued every six months.

Jason Ziedenberg of the Justice Policy Institute, a group that seeks alternatives to incarceration, said the new numbers showed an “alarming growth” in an already overburdened prison system.

“Billions of public safety dollars are absorbed by prison expansion and limits the nation’s ability to focus on more effective strategies to promote public safety,” he said.

Officials at the Drug Policy Alliance, another group opposed to long prison sentences for drug offenders, said the drug policies of the past 30 years have been a major contributor to the U.S. prison population explosion.

According to the International Centre for Prison Studies at King’s College in London, the United States has long had the world’s largest prison population, followed by China at 1.5 million and Russia at 885,670.