Students still shaken from the deadly mass shooting at an Oregon community college days ago were welcomed back to campus on Monday by grief counselors, comfort dogs and words of encouragement from faculty, but classes remained canceled through the week.

The White House later in the day said President Barack Obama, who spoke out forcefully in favour of stricter gun control measures after the massacre, planned to visit Roseburg on Friday to meet privately with families of the victims.

Roseburg Mayor Larry Rich, a Republican and self-described supporter of gun rights in the former timber community 180 miles (300 km) south of Portland, said he welcomed the Democratic president to visit when the White House called on Monday to ask whether Obama should make the trip.

"I said, 'Yes, he should come here. He's our president and we would love to have him here,'" the mayor said. He added that if there were a funeral for any of the victims the day of Obama's visit, the president would attend.

The first such service has been scheduled for Thursday, one week after the killings, for Jason Johnson, 33, who was slain with seven other students and their English professor by a troubled classmate.

Nine more people were wounded in the rampage, which ended with the gunman taking his own life.

Four days after the shooting spree, the campus of Umpqua Community College was reopened to students and staff to allow them to retrieve vehicles and other belongings left behind in the pandemonium of last Thursday.

The reopening also was aimed at helping restore a sense of normality on campus before classes and other activities at the college of some 13,000 students – about 3,000 enrolled full time – were set to resume next Monday, school officials said.

The college, situated on a bend in the North Umpqua River, was peaceful as staff and students milled about in the sunshine.

"Road to recovery"

But an atmosphere of trepidation prevailed among some of those venturing to school on Monday.

"The anxiety of walking back on campus is very real," student Jared Norman said in a text message to Reuters, adding that his campus visit "begins the road to recovery".

Those arriving on Monday were greeted by teams of volunteers with six golden retrievers from the national K-9 Comfort Dogs network run by Lutheran Church Charities.

Emotions were readily apparent in the occasional hugs and tears students and staff shared with one another across campus.

In an open letter published on Monday, faculty members expressed gratitude for the community's support and vowed solidarity with students struggling to comprehend the tragedy.

"We will learn some things with you this year that were not on the syllabus," the letter said. "We don't know exactly what that will look like yet, but we will learn about it together as we move forward."

The college bookstore also reopened, and college staff converted a portion of an outdoor amphitheatre on campus into a shrine – adorned with flowers, candles, balloons and the names of the fallen professor and students, as well as a banner with the message: "UCC Strong / We will prevail together."

Scene of the crime

A short distance away stood Snyder Hall, the brown, single-story, tile-roofed building where last week's carnage unfolded, now partly veiled behind a barrier of chain-link fencing and black tarpaulin erected around the crime scene.

Law enforcement was not readily visible in the center of campus, but a mobile command post of the Douglas County Sheriff's Department remained set up in the parking lot.

The sunny, quiet tranquility stood in stark contrast to the fear that gripped the campus last Thursday in the midst of the deadliest US mass shooting in two years.

A gunman, Christopher Harper-Mercer, 26, stormed into his writing class to shoot his professor, then began picking off cowering classmates one at a time as he questioned them about their religion, according to survivors' accounts.

Parents of two survivors revealed over the weekend that the assailant had handed an envelope to one of the male students in the class, whose life the suspect deliberately spared. CNN reported on Sunday that the envelope contained a computer flash drive that was turned over to authorities.

Authorities said Harper-Mercer, who moved from the Los Angeles suburb of Torrance, California, to Oregon with his mother in 2013, carried six guns and extra ammunition with him to campus the day of the killings. Another eight firearms were found at the apartment near campus where he lived with his mother, officials said.

Authorities have revealed little of what they may know about Harper-Mercer's motives.

People who knew him casually have described Harper-Mercer as a socially awkward loner. After a brief, failed stint in the US Army, he graduated from a school that catered to students with learning and emotional disabilities.

He was by all accounts preoccupied with guns, a passion he was reported to have shared with his mother, who spent time with him at target ranges.

The head of a private firearms academy in Torrance has said Harper-Mercer sought to register for classes there in 2012 or 2013 but was turned away because he was found to be "weird" and overly eager for high-level weapons training at his age.