Four men found decapitated as Mexico drug war rages

(Corrects first name of kingpin in 3rd paragraph)

MEXICO CITY, July 2 (Reuters) - The severed heads of four men were found dumped on a Mexican street on Wednesday with a message accusing a drug gang kingpin of treachery, police said.

Neighbors in the northern city of Culiacan found the men's bodies wrapped in plastic sheets and a blanket, with their heads stuffed into white plastic bags.

An obscenity-laden note scrawled onto a piece of cardboard invited Joaquin "El Chapo" (Shorty) Guzman -- the head of the Sinaloa drug cartel -- "to see what his stupid acts had caused."

Guzman, who is considered Mexico's most-wanted man, is battling a rival gang led by his one-time ally Arturo Beltran Leyva, whose hitmen reportedly killed one of Guzman's sons in May.

In a separate incident in the same city, police said they killed four suspected drug gang members in a shootout.

More than 1,600 people have died so far this year in drug violence as gangs battle for control of lucrative trafficking routes and as the government has stepped up anti-smuggling operations by deploying thousands of army troops. (Reporting by Anahi Rama and Jason Lange)