The federal government is advising Canadians to stay away from northern Mexican cities to avoid drug cartel warfare -- violence that could be linked to drug smuggling in B.C.

Mexican authorities say three workers from the American consulate were mistakenly shot on Sunday in and around the city of Ciudad Juarez by drug cartel assassins.

They were among nearly 50 people who were murdered in drug-related violence in Mexico over the weekend.

That led to a travel advisory from the Ministry of Foreign Affairs on Tuesday, warning Canadians to avoid Ciudad Juarez, where federal troops are battling drug cartels.

An estimated 18,000 people have been killed in Mexico in just four years. Though Mexico is a long way from B.C., the illicit drug economies are linked.

On March 5, RCMP in Port Hardy, B.C., seized a sailboat loaded with more than 1,000 kilograms of cocaine worth about $100 million. It had sailed to Vancouver Island from Panama.

A Victoria man and a Mexican national were arrested and later charged in connection with what police believe could be an international drug-smuggling operation.

"The actual quantity is clearly indicative of both localized and national -- and potentially international -- distribution of cocaine from British Columbia," Supt. Brian Cantera of the RCMP's Federal Enforcement Branch told CTV News.

Cocaine can't be manufactured in Canada, but its importation is thought to be financed in B.C. by marijuana farms and synthetic drug factories.

Police can't confirm which criminal organization ordered the cocaine seized in Port Hardy.

But Rob Gordon, a criminologist at Simon Fraser University, speculated that biker gangs could be involved.

"The first group you think about when you see something on this scale is the Hells Angels or Hells Angels in a consortium with other groups," Gordon said.

Meanwhile, Brad Davies, a Vancouver travel agent with Virtually There travel, said that vacationers heading to the south of Mexico should not be concerned about the government warning or cartel violence.

"The violence is confined to the border towns, and the major resort towns…have not been affected at all," he said.

With a report from CTV British Columbia's Lisa Rossington