REYNOSA, Mexico (AP) – This border city and others near the eastern end of the United States border escaped the worst of Mexico’s bloody drug war for years, but now the bodies are piling up, several journalists are reportedly missing or dead and once-busy streets are empty after dark.

The crumbling of an alliance between two Mexican drug gangs has plunged the 320-kilometer stretch of border into violence, raising fears of a new front in the drug war, a US anti-drug official told The Associated Press.

In Mexican border cities stretching from Matamoros near the Gulf to Nuevo Laredo, gunfire has been heard almost daily, and at least 49 people were killed in drug war-related violence in less than six weeks.

Reynosa’s main plaza and Calle Hidalgo, a pedestrian shopping street, still bustle during the day. Shoeshiners were doing brisk business on a recent afternoon. But the streets are deserted by evening, clothing store manager Manuel Diaz said.

“I imagine they (shoppers) are scared, because there are no customers in the street,” he said. Diaz himself kept his children home from school last month when rumors of abductions terrorized parents and many schools suspended classes.

Drug gangs have set up vehicle “checkpoints” along highways to the US border, apparently to look for their rivals, according to the US Consulate in Monterrey, two hours south of the Texas border. As a result, the US Consulate offices in the area had restricted travel of their employees to Reynosa, but lifted that ban Monday.

While the Pacific coast city of Tijuana and Ciudad Juarez, across from El Paso, Texas, have long been wracked by open warfare among rival cartels, border cities to the east had enjoyed relative calm under The Company, a drug-trafficking duopoly formed by the Gulf cartel and the Zetas.

The tenuous union was broken when a member of the Zetas was killed in Reynosa in January, perhaps because he was in the Gulf cartel’s territory without properly announcing himself, said Will Glaspy, head of the US Drug Enforcement Administration office across the border in McAllen, Texas.

The Zetas — a gang comprised of former Gulf cartel hit men — demanded that the Gulf cartel hand over the men responsible. Battles followed when the Gulf cartel refused, Glaspy said.