WASHINGTON -- Customs and Border Protection officials are serving notice that the possession of cannabis is against federal U.S. law -- and that their policies and procedures won't change just because it's legal in Canada.

Executive assistant commissioner Todd Owen says border officers will have "broad latitude" to determine whether someone who admits to using marijuana should be deemed inadmissible to the United States.

He says the American laws, policies and procedures that exist today will still be in place Wednesday after Canada's legalization measures formally take effect.

Owen says a person's admissibility depends on an array of factors, including whether a border guard has reason to believe that someone who consumes pot in Canada has plans to do so upon entering the U.S.

Officials also say that because a legal amnesty granted in Canada doesn't apply in the U.S., someone who was pardoned of a previous pot conviction north of the border won't be able to enter the country simply because it's been legalized.

As of Wednesday, Canada will be the first G7 member to greenlight legal recreational pot -- a move Prime Minister Justin Trudeau has justified as an effort to better protect young people from the drug's effects and eliminate the influence of organized crime