Gunmen stormed a party in northern Mexico on Sunday and massacred 17 people, authorities said.

The gunmen arrived at the party in Torreon in several cars and opened fire without saying a word, the Coahuila state attorney general's office said in statement. At least 18 people were wounded.

Several of the victims were young and some were women, but their identities and ages had not yet been determined.

Investigators had no suspects or information on a possible motive.

Police found more than 120 bullet casings at the scene, most of them from .223 calibre weapons.

Coahuila is among several northern states that have seen a spike in drug-related violence that authorities attribute to a fight between the Gulf cartel and its former enforcers, known as the Zetas.

In May, gunmen killed eight people at a bar in Torreon. Later that month, a television station and the offices of a local newspaper came under fire. A pregnant woman was wounded in the attack on the offices of Noticias de El Sol de la Laguna.

Across northern Mexico, there have been increasing reports of mass shootings at parties, bars and rehab clinics.

Shooting killed 19 at rehab centre

In the worst such massacre this year, gunmen raided a drug rehab centre in the northern city of Chihuahua and killed 19 people. In January, gunmen barged into a private party in the border city of Ciudad Juarez and killed 15, many of them high school or university students.

Relatives say it was a case of mistaken identity, while state officials claim someone at the party was targeted, although they have not said who it was.

The massacre in Torreon came three days after the first successful car bombing by drug cartels introduced a new threat in Mexico's raging drug war.

Drug gang members detonated the bomb after luring federal police and paramedics to the scene in Ciudad Juarez by shooting a bound man dressed in police uniform and calling in a false report of a wounded officer. Three people were killed, including a federal officer and a private doctor who had rushed to the scene to help.

Officials say 24,800 people have been killed in drug gang violence since President Felipe Calderon declared war on the cartels in December 2006, deploying soldiers and federal police to fight traffickers in their strongholds.

The government attributes much of the rise in violence to infighting among drug gangs whose leadership has been splintered after the arrest of kingpins.