SAN JUAN  - Feuding drug gangs opened fire in a crowded bar in Puerto Rico over the weekend, killing eight people, including the unborn child of a pregnant woman who was wounded, police said on Monday.
A 9-year-old girl was also among the 20 injured. The shooting at the La Tombola bar in Toa Baja, a suburb of the capital San Juan, was one of the worst in the history of the U.S. Caribbean island territory, which is a transit point for drugs being smuggled to the United States.

Gunmen with automatic weapons entered the bar late on Saturday and opened fire on a crowd there celebrating its reopening. Several patrons drew weapons and fired back.

This is a result of a dispute over control of drug sales points, Police Superintendent Jose Figueroa Sancha said.

When these people entered that bar ... They were not thinking of the innocent, he added.

Federal and local authorities last month arrested Angel Ayala Vazquez, know as Angelo Millones, who police said was the leader of a gang on the island's north coast that trafficked drugs to the U.S. mainland.

Also last month, U.S. agents arrested 21 people, nine of them American Airlines employees, accused of smuggling suitcases loaded with cocaine on flights from Puerto Rico to the United States.

The killings in Puerto Rico came at a time of heightened labor tensions on the island of nearly 4 million people, which is a major Caribbean tourism destination as well as a manufacturing hub for petrochemical, pharmaceutical and technology companies.

But Puerto Rico has been badly hit by the economic recession, and its unemployment rate was 15.8 percent in August, higher than any U.S. state.

On Thursday, tens of thousands of Puerto Rican public workers shut down the center of the capital San Juan in a one-day general strike to protest against the layoff of thousands of workers announced by Governor Luis Fortuno.

(Writing by Pascal Fletcher; editing by Jackie Frank)