Frustration mounted Monday among the Fort McMurray evacuees, crammed into shelters after a traumatic flight from the Canadian oil city, as some turned to criticizing the official handling of the wildfires ravaging the region.

At the closest evacuation center to the fires, in Lac La Biche, about 300 kilometers (185 miles) south of Fort McMurray, security was doubled overnight and entry has become more tightly controlled.

"People are tired, they're frustrated, they feel helpless, and sometimes they just lash out," said security guard Mustafa Abraham.

Abraham said half a dozen people had been briefly taken into custody by municipal peace officers and security guards, mostly for drunkenness or unruliness.

A special room was set up for rowdy evacuees.

Nearly 400 evacuees are staying semi-permanently at the center, one of 11 set up across Alberta province for the 100,000 residents of Fort McMurray, who were told they would not be allowed home for at least two more weeks.

Adding to the tensions, a number of evacuees with addictions are going through severe withdrawal, said shelter officials, who are enforcing a zero tolerance policy for drugs and alcohol.

In the gymnasium of the local high school, which has served as a cafeteria for evacuees since last Wednesday, a scuffle broke out.

Security guards rushed to separate the two women, who were cousins, and escort them away.

"Tensions are boiling over," said one evacuated resident, Donald Janvier.

The town of 3,000 swelled in population over the last week, providing food, accommodation and clothing to nearly 10,000 evacuees, although most have since moved on to Edmonton or other major cities.

- Evacuees praise volunteers -

In campgrounds and roadside motels, where evacuees spent days trading tales of the harrowing escape, the talk has since turned to questioning the fire response and the political leadership in the province of Alberta.

Evacuee Elmer McDonald of the Athabasca Chipewyan First Nation, which is under a state of emergency, said the response got off with a weak start.

"The fire was small at first. They didn't respond fast enough (to douse it) and now it's become huge," he said, sitting outside a motel in Lac La Biche.

"It wouldn't have become a Can$9 billion disaster if someone had just thrown a bucket of water on the fire back then."

The social media conversation has taken a similar turn.

The nation's flagship airline was denigrated over sky-high fares charged to evacuees last Wednesday.

Air Canada has since apologized, saying rates for last-minute bookings are automatically set higher. It's now offering customers refunds.

However critical of the government, evacuees were full of praise for the work done by volunteers.

At a camp for pipeline workers at nearby Wandering River that opened its doors to evacuees, a yoga class was offered Sunday night to help people de-stress after the trauma of the evacuation.