Three suspects have been detained in an April 20 bar shooting in the northern Mexican city of Chihuahua that left 16 dead, prosecutors said.

The Chihuahua state Attorney General's Office said Jaime Cuevas Baeza, 33; Jesus Manuel Valenzuela Dominguez, 48; and Ivan Enrique Montañez Martinez, 31, were arrested in a tactical and intelligence operation.

The suspects were detained Thursday afternoon in the Unidad Proletaria neighborhood of Chihuahua city, the state capital. They were riding in a van without license plates in which authorities found a loaded firearm.

According to the official statement, the detainees confessed at the time of their arrest and when questioned by prosecutors, with attorneys present, to committing the murders at the El Colorado bar.

It added that ballistics experts were trying to determine whether the confiscated weapon was the one used in the April massacre, as one of the detainees told investigators.

"In their statements to the state AG's office, (the suspects) said that on April 20 they and other individuals received instructions to go to the El Colorado bar to kill whomever they found inside," the statement said.

It added that the three suspects' statements coincide with investigators' findings based on information and evidence gathered at the crime scene.

The statement said the investigation into the shooting that left 16 dead, including two journalists, was ongoing and was given a boost by Thursday's arrests.

On Feb. 4, gunmen killed nine people, including a police officer and five musicians, and wounded 11 others in a shooting attack on another bar in Chihuahua city.

Chihuahua state, which borders Texas and New Mexico, has been among the hardest hit by violence in recent years pitting drug cartels fighting over smuggling routes to the United States.

Much of the violence there has occurred in and around Ciudad Juarez, a hardscrabble metropolis across from El Paso, Texas.

More than 50,000 people, according to official figures, have died in drug-related violence since late 2006, when outgoing President Felipe Calderon took office and militarized the struggle against the country's heavily armed, well-funded cartels.

The Movement for Peace with Justice and Dignity, which was founded by human rights activist and poet Javier Sicilia, puts the death toll at 70,000. EFE