WINNIPEG/CALGARY (Reuters) - Canada’s gun control laws ban dozens of assault rifles, but some permitted firearms are easily modified for greater damage, and more lax regulations in the United States make smuggled weapons accessible, experts said after a rare Canadian mass shooting on Sunday.

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A man was charged on Monday with six counts of first-degree murder and five counts of attempted murder with a restricted weapon in the shooting at a Quebec City mosque.

Police have not commented on the type of gun used, but sources said it was a semi-automatic weapon.

Semi-automatic guns can legally hold magazines up to five rounds in Canada, but many military-style semi-automatics are easily modified to 30 rounds, said A.J. Somerset, an author on gun issues.

And while some rifles are banned by name, knock-offs are allowed, he said.

“Canada’s classification system is a mess,” Somerset said. “If someone wants to do the shooting at the mosque, they can obtain a non-restricted firearm in Canada that is functionally the same as an AK-47, illegally modify it, and they have exactly the rifle we don’t want them to have.”

Handguns in Canada are far tougher to obtain than in the United States. Canadians must obtain licenses and endure safety training and extensive checks that delve into the potential owner’s criminal record, mental health and third-party references.

A restricted class of guns must be registered for tracking, while fully automatic weapons are prohibited.

The tight restrictions have opened up an illegal flow of guns from the United States. In Quebec, gangs may contribute to availability of illegal guns, since smuggling is done through networks, Somerset said.

“There is an illegal market for all manner of weapons that are openly available in the U.S,” Rob Gordon, a criminology professor at Simon Fraser University in British Columbia, said.

“The link to organized crime is quite profound, so where you see organized crime in Quebec, B.C. and Ontario ... they seem to have access to these types of weapons.

Quebec has a higher rate of gun licences per 100,000 residents than Ontario and British Columbia, but lower than most other provinces and territories, according to government statistics.

Quebec lawmakers passed a bill last year to launch a provincial gun registry in 2018.