The number of serious crimes reported in the Mexican capital fell 12.6 percent in the first half of this year compared with the same period in 2010, according to figures compiled by the city prosecutor's office.

Reports of offenses such as homicide, kidnapping, robbery and vehicle theft declined from 31,562 to 27,574.

Muggings and auto thefts together accounted for more than 18,000 of the crimes addressed in the semi-annual Rinde report.

Municipal police dismantled 53 criminal gangs in the January-June period and arrested a total of 7,179 people suspected of perpetrating "high-impact" crimes, the report says.

A study released last year by the prestigious Monterrey Institute of Technology indicates that only 22 percent of crimes in Mexico are reported, while a mere 2 percent of criminal complaints lead to convictions.

Mexico City's mayor, Marcelo Ebrard, now holds the rotating chairmanship of the National Governors Conference, or Conago, which last month launched a coordinated, high-profile offensive against street crime.

While the operation resulted in nearly 4,000 arrests across Mexico's 31 states and the capital region, it remains unclear how many of those people will actually face charges.

Conago says it hopes to mount more such operations in the future.