The gunman behind the latest mass shooting in the US had hoarded an arsenal of weapons and was enrolled in the class where the fatal shootings occurred, authorities have said.

The names of the nine people, five women and four men, aged between 18 and 67, who died on Thursday's shooting at Umpqua Community College were released on Friday.

Though officials have yet to formally name him, the gunman, who died in a shoot-out with police, has been widely identified as Chris Harper Mercer, 26.

Officials said they had recovered 13 weapons belonging to him, including six at the school and seven at the apartment he shared with his mother.

A flak jacket and five rounds of ammunition were also recovered at the school after the shooting.

US media said Mercer left behind a typed statement several pages long in which he indicated he felt lonely and was inspired by previous mass killings.

Seven other people were wounded in the attack in Roseburg, about 180 miles south of Portland.

Mercer's weapons had been purchased legally over the past three years, some by him, others by relatives, said Celinez Nunez, assistant field agent for the Seattle division of the Bureau of Alcohol, Tobacco and Firearms.

Oregon's top federal prosecutor said Mercer used a handgun when he opened fire on classmates and stashed a rifle in another room but did not fire it.

Douglas County Sheriff John Hanlin said on Friday that Mercer was enrolled in the class where the fatal shootings occurred.

Rita Cavin, interim president of the school, told CNN that Mercer was enrolled in English and theatre classes and that he initially opened fire in an English class.

Special school

The army revealed that Mercer had failed basic training in 2008.

Army spokesman Lieutenant-Colonel Ben Garrett said Mercer was in the military for a little over a month at Fort Jackson, South Carolina, but was discharged for failing to meet the minimum standards.

Garrett did not say which standards Mercer failed.

Generally, the army requires recruits to pass physical fitness tests and to be in overall good physical and mental health.

Recruits must also pass a multiple-choice test covering science, mathematics, reading comprehension and other topics.

Mercer graduated from the Switzer Learning Center in Torrance, California in 2009, according to a graduation listing in the Daily Breeze newspaper.

Switzer is a private, nonprofit school geared for special education students with a range of issues from learning disabilities, health problems and autism or Asperger Syndrome, according to the school's website.

In Washington, President Barack Obama lamented the government's inability to pass stricter gun laws even after attacks like the one in Oregon.

At a news conference at the White House on Friday, Obama said he planned to keep talking about the issue and "will politicise it" because inaction is itself a political decision the US is making.

He said it was impossible to identify mentally ill people likely to perpetrate mass shootings ahead of time.

The only thing the US can do, he explained, is ensure they do not have an arsenal available "when something in them snaps".

Source: Agencies