Gunmen killed the leader of Mexico's leftist Democratic Revolution Party in the southern state of Guerrero, authorities said Thursday.

The killing prompted Guerrero's governor to cut short a trip to the United States aimed at convincing cruise ship lines that the state's flagship resort, Acapulco, is safe enough to bring their ships back for visits.

Some cruise ships have stopped visiting the Pacific coast state because of continued violence, like the assassination late Wednesday of leftist politician Demetrio Saldivar. The state prosecutors' office said Thursday that Saldivar was killed in the state capital, Chilpancingo. The office said a witness watched as two men blocked Saldivar with a car, then shot him to death before fleeing.

Saldivar was the state general secretary of the PRD party in Guerrero. Local media reported he had previously occupied a post in the state government.

Also, Thursday, officials in Chilpancingo reported the discovery of three dismembered bodies of two men and one woman in bags outside a restaurant in the state capital. There was no immediate word on their identities.

Guerrero was plagued by political violence in the 1990s, but has been hit even harder by drug gang violence in recent years.

The U.S. cruise line Holland America announced in March that it had halted port calls at Acapulco and would sail to other destinations in Mexico "due to recent security concerns."

A few other cruise lines continue to make port calls in Acapulco, but those visits began to fall off steeply around 2010.

Gov. Hector Astudillo traveled to Miami to try to convince cruise ship operators that safe perimeters had been established for passengers in Acapulco and the resort of Zihuatanejo.

But Astudillo tweeted that Saldivar's killing forced him to cut the trip short.

"These regrettable events have forced us to cancel the planned working trip and return to Guerrero as soon as possible," Astudillo wrote in his Twitter account.