Updated

Gunmen burst into a bar called "Desesperados" in the Mexican border city of Ciudad Juarez and opened fire on Sunday, killing five people and wounding nine others, authorities said.

Assailants also killed the state's prisons director and his son in a second attack in the area, which has turned into a deadly battleground for warring drug cartels.

Gunmen opened fire on the vehicle carrying Chihuahua prison director Gerardo Ortiz and his son in Chihuahua city, the state capital, located south of Ciudad Juarez. The state's prisons used to be the site of frequent battles between gangs, but deaths in such disputes had appeared to decline over the last year.

Authorities offered no motive for the attack in the "Desesperados" — or "The Desperate Ones" — bar early Sunday. The nine wounded were listed in serious condition at hospitals in Chihuahua state, were Ciudad Juarez is located, according to state prosecutors' spokesman Fidel Banuelos.

More than 4,000 people have been killed in Ciudad Juarez in drug-related violence in the last two years, giving the city one of the highest murder rates in the world.

Also Sunday, police in the Pacific coast resort of Acapulco found the bound, bullet-ridden bodies of five men on the outskirts of the city, according to police in Guerrero state, where Acapulco is located.

Also in Guerrero state, detectives reported they had found the bodies of two more men buried in a clandestine gave in a coconut grove where 18 bodies had been unearthed last week.

The 18 were among 20 men from the western state of Michoacan who were kidnapped Sept. 30 while visiting Acapulco. Two men remained to be found.

The two badly decomposed bodies had been buried for about five weeks at a site near the first grave, characteristics that would suggest they are the missing Michoacan men.

Fernando Monreal Leyva, the director of the state detective agency, said experts will have to wait until the bodies are identified by relatives, possessions or DNA tests before they can confirm their identities.

Police began digging at the site after a video appeared on Youtube in which two men — their hands apparently tied behind their backs and answering questions from an unseen interrogator — say they killed "the Michoacanos" and buried them in the area.

Two bodies wearing the same clothes as the pair seen in the video were later found on top of the first grave, along with a sign reading: "The people they killed are buried here."

In the video, the two men say they killed the "Michoacanos" in an act of revenge against La Familia, a drug cartel based in Michoacan.

The families of the 20 missing men say they were mechanics in the state capital of Morelia who saved up money to take a vacation together.

It was unclear whether the men were mistaken for cartel members, or were killed simply because they were from the cartel's home state.