The number of homicides in Mexico rose by nearly a quarter in 2010 compared to the year before as the drug war intensified across the country, Mexican statisticians said.

The National Institute of Statistics and Geography recorded 24,374 homicides over the course of last year, a 23-percent increase from 19,803 in 2009. Last year's figure represented 22 killings for every 100,000 residents in the country.

Many but not all of the homicides were committed by organized crime organizations, the institute told The Associated Press.

According to the statistics institute, the U.S.-bordering state of Chihuahua saw the highest number of homicides with 4,747. Sinaloa, in northwestern Mexico, registered 2,505.

Sinaloa is the headquarters of the Sinaoloa cartel, while Chihuahua includes the violent border city of Ciudad Juarez. Those two states are among the most affected by drug violence, and together they accounted for 29 percent of Mexico's homicides.

The institute cautioned that its information was preliminary and said it awaited definitive results that are to be released in September.