(NewsNation) — Footage aired recently by a Mexican television station shows women armed with assault rifles on the move with male cartel members, in what is described as a new “phenomenon” in organized crime.

According to one expert who trains American law enforcement on cartel activity, female cartel members are not new, but their numbers are on the rise.

“They don’t want to be the cartel wife of the old days, they want part of the action,” said Robert Almonte, a security consultant. “They love the action, they love the excitement, they love the money, and they want to be able to call some shots also.”

With a lucrative drug war raging in Mexico, more women are becoming assassins, too. The “sicarias,” as they are known, are a major asset for cartels.

“So, it could be a very pretty girl that you say, there’s no way this girl works for the cartel, or if she does work for the cartel, she’s definitely not a killer, and then they find out that that’s not the case,” Almonte said.

There is no estimate on how many female assassins, or even arsonists, the cartels are now using. A few women have themselves been killed in Mexico.

A reporter for Mexico’s Milenio TV, which aired the footage of balaclava-clad women with guns, said it is a “phenomenon that had not been recorded before,” the Mirror reported. Officials who spoke with Milenio TV said the presence of women in cartels has “increased in recent months.”

Almonte predicted an eventual spillover effect north of the border.

“It’s only going to be a matter of time before we see the women members of the cartel here in the United States playing a larger role in the cell groups here, and maybe even acting as assassins here in the United States,” Almonte said.

Law enforcement research indicates that cartels are still very much male-dominated. But in recent years, more women have been on the rise in more active and deadly roles.