El Chapo's sons bar fentanyl production in Mexican state, according to banners

It is unclear who put up the banners, festooned to bridges and overpasses. They appeared at a time when US authorities are ramping up pressure on Mexico to take action against crime groups involved in fentanyl production.

A powerful faction of the Sinaloa cartel led by the sons of ex-Mexican drug lord Joaquin "El Chapo" Guzman has banned fentanyl production and sales in Sinaloa, according to roadside banners, though analysts doubted the group would leave such a profitable business.

The banners that appeared in the northern Sinaloa state in Mexico on Monday, known as "narcomantas", were signed by Los Chapitos, a grouping of brothers who took over their father's criminal empire when Guzman was extradited to the United States in 2017.