15 shot dead, nine hurt in bloody night for Mexico's Monterrey

An unusually violent night around the northern Mexican city of Monterrey has left at least 15 dead and nine wounded, authorities said late Sunday.

The Nuevo Leon state prosecutor's office said in a statement that 12 people died in six bar attacks in the municipalities of Monterrey, Guadalupe, and Juarez late Saturday and early Sunday.

A man and a 14-year-old boy were also shot dead in their car on a highway, and in the city of Linares, a man was killed in a clash between rival gangs after a "quinceanera" coming-of-age party at a private home, the statement added.

No arrests were announced, the Associated Press reports.

An official at the prosecutors' office said the death toll could rise due to the severity of some of the injuries, and it was not immediately clear if the incidents were linked. The official spoke on condition of anonymity due to security concerns.

The Monterrey area has not seen such a deadly night in years. In 2011, 20 people were killed by a group of gunmen at a bar in a central neighborhood of the city. The following year another attack at a bar nearby killed left eight dead.