Attacks in the home state of Mexico's most powerful drug cartel left 24 people dead and 17 of the victims' bodies were found burned in two pickup trucks, officials said Wednesday.
Authorities are investigating whether the attacks in the Pacific Coast state of Sinaloa are related.
Neighbors called police after seeing a pickup truck on fire early Wednesday in the Antonio Rosales neighborhood of state capital Culiacan, said state Attorney General Marco Antonio Higuera Gomez.
Investigators found 12 bodies in the back of the truck, some of them handcuffed and wearing bulletproof vests, Higuera said. Authorities are trying to determine if some of the victims were part of a group of nine people, including three police officers, who were kidnapped in the town of Angostura on Monday.
Minutes after the first fire was reported, authorities received another call about a truck burning behind a store. Police found four bodies inside that vehicle. All the victims had been shot.
Hours later, Mexico's federal Interior Department _ which is in charge of domestic security _ issued a statement saying it "energetically condemned" the killings, and placed the number of dead in the two vehicles at 17.
Also Wednesday in Sinaloa, four men were shot to death in the town of Mocorito and another three were killed in the town of Guamuchil, Higuera said.
Sinaloa is the cradle of the powerful Sinaloa cartel, led by Mexico's most wanted fugitive, Joaquin "El Chapo" Guzman. The cartel has been fighting the Beltran Leyva cartel in the state since the gang split off in 2008.
Mexico's drug war has claimed more than 35,000 lives nationwide since President Felipe Calderon deployed thousands of soldiers and federal police in late 2006 to crackdown on drug cartels, according to the government. Others put the death toll at 40,000.
A survey released Wednesday found few Mexicans believe the government can defeat drug cartels.
The poll shows 14 percent of those questioned believe Calderon's strategy is succeeding, compared to 23 percent in a poll released in March 2010. The survey by the Mitofsky polling agency also found that 44 percent think the situation won't improve during Calderon's last year in government, which ends in December 2012.
The survey was carried out through face-to-face interviews with 1,000 people from Oct. 21-24. It has a margin of error of 3.1 percentage points.
The turnaround in opinion is a reflection of the public's growing impatience with the crackdown, said Juan Francisco Torres Landa, general secretary of Mexico United Against Crime, which sponsored the poll.
"This reflects the perception that Mexico United Against Crime shares, which is that concrete actions are not being taken to correct the path of President Felipe Calderon's fight against organized crime," Torres said.
Associated Press writer Carlos Rodriguez in Mexico City contributed to this report.