US President Barack Obama has said the United States is the only country on earth that witnesses mass shootings every few months.
Mr Obama was speaking after a gunman killed nine people at a community college in the US state of Oregon.
20 people were wounded in the attack before the gunman was shot dead by police officers.
"Somehow this has become routine," Mr Obama said at the White House in response to the shooting by a 20-year-old gunman at Umpqua Community College in rural Roseburg.
"We can actually do something about it, but we're going to have to change our laws," Mr Obama said. "It cannot be this easy for somebody who wants to inflict harm on other people to get his or her hands on a gun."
Mr Obama said "we've become numb to this" as he angrily repeated that gun laws in the US need to be changed.
Barack Obama has called for changes to US gun laws in the wake of the Oregon shooting https://t.co/rUbNEuOrYC
— RTÉ News (@rtenews) October 1, 2015
The shooting is the latest incident of gun violence in the US, raising demands for more gun control and more effective treatment of the mentally ill.
Douglas County Sheriff John Hanlin said the gunman was shot in an exchange of gunfire with police officers in a campus building.
"It's been a terrible day," Mr Hanlin said.
He did not say how many people had been killed or wounded at the college in Roseburg, a city of about 20,000 people some 418 km south of Portland.
"This is a peaceful community," he said. "We have our share of crime like any community but certainly this is a shock to have this level of a crime."
In an emergency call from the incident posted onto the website of the Oregonian newspaper, an emergency responder at the scene said there were unconfirmed reports the shooter had a long gun.
A short time later, an emergency responder radioed that the suspect was "down."
The Oregonian also said that at least six people were critically injured in the shooting, citing an official with Life Flight.
Update: Photos taken by NR Today show the scene of Thursday's shooting at an Oregon college https://t.co/5fUT51Nwnv pic.twitter.com/eDI8l1hvU4
— KTLA (@KTLA) October 1, 2015
Scenes from the mass shooting at Umpqua Community College in Oregon https://t.co/0wURHXWn8k
— RTÉ News (@rtenews) October 1, 2015
Andi Dinnetz, an 18-year-old freshman at Umpqua, said she was in the building next to where the shooting took place and hid in a welding shop along with a teacher and classmates until a police officer arrived.
She said she was "fine, but shaken."
"They walked us straight through the crime scene with our hands up," Ms Dinnetz said. "It was more tense outside. In the classroom, everyone was trying to make jokes and keep it from being as serious as it was."
Roger Sanchez, a testing coordinator at the school, said students came running into the building where he worked.
"They came in running and we went into lockdown," Mr Sanchez said. "I knew it was serious."
Mercy Medical Center in Roseburg said on Facebook that the hospital had received nine patients from the shooting and had been advised that three more were en route.
Local media reported that authorities were combing through the campus, which serves more than 13,000 students, 3,000 of them full-time.
The FBI said it was sending agents to the scene. Term began at the college on Monday.
The Douglas County Sheriff's Office said students and faculty members were being bused to the nearby fairgrounds where they could be picked up.
The FBI said agents were responding from offices in Medford,Eugene, Salem and Portland.
The Oregonian said agents from the US Bureau of Alcohol,Tobacco, Firearms and Explosives were also en route to Roseburg.
A chain of messages posted to an anonymous chat board known for its explicit conversation threads and graphic images included a warning on Wednesday evening not to go to school yesterday "if you are in the northwest."
The anonymous postings and numerous replies appeared on the site 4chan.org.
Reuters viewed the thread but could not verify its authenticity or whether it had any connection to the shooting. Emailed questions to federal law enforcement officials about the postings were not immediately answered.
Recent episodes of gun violence in the United States include the massacre of nine people at a South Carolina church in June and the killing of five US servicemen in Chattanooga, Tennessee.
In 2012, seven students at the small Christian college Oikos University in Oakland, California, were shot dead by a former student, marking the deadliest outburst of violence at a US college since April 2007, when a student at Virginia Tech University killed 32 people and wounded 25 others before taking his own life.
