Updated

Eight people were killed in Acapulco on a particularly bloody Sunday for Mexico's violence-plagued Pacific coast resort city, while at least 12 bodies were found in a clandestine grave elsewhere in southern Guerrero state.

"It was a horrible day," said Roberto Alvarez, security spokesman for Guerrero state, which is home to Acapulco.

The violence began early when police were alerted to the bodies of three young men found with tourniquets around their necks and signs of torture in the San Agustin neighborhood on Acapulco's northern outskirts.

Later in the morning, a gunbattle broke out between police and armed men on a central avenue, setting off a chase that ended with one suspect killed and three arrested.

Still before noon, two gunmen stormed into a bar and fatally shot a man and a woman who were drinking there. Police patrolling nearby responded and caught the attackers.

The suspects told police the bar contained a clandestine grave, and an excavation by authorities turned up the bodies of four men and one woman. Authorities said they were resuming the search Monday on the belief that more bodies could be hidden on at least two adjacent properties.

On Sunday afternoon, gunmen killed two men two blocks from the same central avenue where the police chase had taken place earlier. Neighbors found the bodies and notified police.

Elsewhere in Guerrero, state authorities reported six burned bodies, six skulls and two sets of bones were found in the municipality of Copanatoyac.

Alvarez, the state security spokesman, said the remains found in the clandestine body-dumping ground might represent between 12 and 14 people.

Officials were also working to confirm reports of killings in the Guerrero cities of Iguala, Taxco and Tlapa.

The state has been among Mexico's worst hotspots for drug gang violence in recent years. Guerrero recorded 1,726 homicides from January through September, according to federal statistics, up slightly from 1,654 during the same period last year and well more than any other state in the country.