Mexican officials say kidnappings have jumped 8.7 percent over an eight-month period despite stepped-up arrests.

National Public Safety System director Jorge Tello says 774 kidnappings were reported nationwide from September 2008 to April 2009, compared to 707 during the preceding eight-month period.

Tello says authorities have improved their response, however, rescuing 671 people in the same period. He says authorities arrested 971 suspected kidnappers and broke up 133 kidnap gangs, an increase of 24.7 percent and 30 percent, respectively.

The government says there are about 97 kidnappings a month, but acknowledges most go unreported because many Mexicans mistrust police.

The nonprofit Citizens' Institute for Crime Studies estimates the real rate is closer to 500 a month.