WASHINGTON -- The owner of a gun store just outside Ferguson, Mo., agreed to chat -- with one condition.

"It's gotta be quick," he said Monday afternoon. "We're extremely busy."

Anecdotal evidence and available statistics from the surrounding county suggest gun sales have been skyrocketing in the area ever since the summer, when the fatal police shooting of Michael Brown touched off weeks of riots, violence and unrest.

The trendline on concealed-carry permits looks a little like a hockey stick.

Figures supplied by the St. Louis County Police Department show this year's applications followed a flat trendline until a sharp curve appeared in August, when Brown -- who was unarmed -- was shot and killed in a confrontation with a white police officer.

They've been rising ever since.

The number of requests in November is already three times that for the same period last year. There's no licence requirement in Missouri for a handgun, but there is one to carry a concealed weapon -- and there were 708 applications for those this month, compared with 233 in November 2013.

Which explains why the owner's a little busy at Metro Shooting Supplies. His store's just across from the St. Louis International Airport, in the suburb next door.

"We've sold several hundred guns in the last few weeks," owner Steven King said. "People think the city is going to have a lot of problems with rioting and looting."

King said sales are up five times since last year -- demand that he believes is being driven entirely by the events in Ferguson.

There was looting three months ago, then accusations of police brutality against mostly peaceful crowds. On Monday, tensions were high once again as area residents nervously awaited a grand jury decision on whether to charge Darren Wilson, the police officer who fired the fatal shots.

The state governor has pre-emptively called a state of emergency. Two men have already been arrested, reportedly in a police sting operation tied to the acquisition of explosives.

To illustrate that fear, King tells the story of one customer.

He says the mother of an eight-year-old girl came in to buy her first gun. Until this month, she'd only been to shooting ranges but had never purchased her own weapon.

"She said, 'If something were to happen to (my daughter) I could never live with myself,"' King said.

Mom wound up spending US$862 at the gun shop.

She left with a Smith & Wesson 9-mm handgun, a storage safe, and a pack of hollow-point bullets.

King said most people don't worry about regular protesters. What concerns them, he said, are "splinter groups" -- individuals who might use crowds as cover to steal. The fear crosses ethnic lines, he said, explaining that his new customers come from different races, ages and backgrounds.

Police are investigating what one media report is describing as an accidental shooting linked to Ferguson fears.

Citing police sources, CNN reported Monday that a St. Louis woman was killed with a gunshot wound to the head Friday. It said her boyfriend told police the gun had been purchased out of fear of unrest, and it went off during a traffic accident.

Events in Ferguson have laid bare racial divides in the country.

That much was evident in a jarring conversation this weekend between ex-New York mayor Rudolph Giuliani and Michael Eric Dyson, a sociology professor at Georgetown University.

It devolved into a near-shouting match, with the host of NBC's "Meet the Press" failing to get a word in edgewise.

Giuliani expressed annoyance that so much attention was being paid to a single shooting by a white police officer -- when, he said, people should be focusing on the 93 per cent of blacks murdered in the U.S., being killed by other blacks.

He said African-Americans should be talking about making their own communities safer, so that they don't require such a heavy police presence.

Shouting past the moderator at his African-American co-panellist, Giuliani said: "White police officers won't be there if you weren't killing each other."

Dyson shot back that black people do worry about community violence. In fact, he said, they talk about it all the time. He accused Giuliani of muddying the police-brutality problem with a false comparison and suggested his statements dripped with the logic of "white supremacy."

Meanwhile, President Barack Obama was on another channel, appearing on a different Sunday talk show.

Obama did what he's often done throughout his presidency, whenever racial incidents occur: he attempted to navigate gingerly between the positions espoused by Giuliani and Dyson.

It was like a one-man debating society, bouncing back and forth between point and counterpoint.

Sometimes, Obama said, black-community concerns about policing are justified. On the other hand, he said, sometimes they're not.

He said minorities live in more dangerous neighbourhoods and do want a police presence. On the other hand, he said, they want police to be properly trained so that they can distinguish between a "gangbanger" and a non-threat.

He described experiencing discrimination as a young man. He said white people -- or, in Obama's more careful wording, "folks on the other side of it" -- might not be sensitive to how racial profiling feels.

On the other hand, Obama said, it's important not to overreact.

"My own experience tells me that race relations continue to improve," Obama said in an interview on ABC's "This Week."

"Just in our lifetimes ... there's no way to say that somehow race relations are worse now than they were 10 years ago, 20 years ago or 50 years ago. Part of what happens is that they get a lot more attention today. Occasionally, problems that used to be pretty common 20 or 30 years ago weren't videotaped.

"Now, you know, somebody's got a camera, and people see it."