MEXICO CITY (Reuters) - At least 43 people were killed in a road accident when a cargo truck crashed into a tour bus in the eastern Mexican state of Veracruz, local government authorities said on Friday.

The early morning collision occurred near the municipality of Alamo Temapache in northern Veracruz, and four minors were among the dead, a municipal spokesman said.

According to initial investigations, the vehicles collided after the truck's trailer decoupled, said Gina Dominguez, a spokeswoman for the Veracruz state government. She confirmed the death toll reported by local authorities.

President Felipe Calderon expressed his sadness over the crash in a message posted on his Twitter account.

"My deepest condolences for the families of those who died in the terrible accident this morning in Veracruz," he said.

The spokesman in Alamo Temapache could not say how many people were injured in the accident, which occurred in a part of Mexico that has been plagued by drug-related gang violence in recent years. Local media put the number at more than 20.

Police reports showed both vehicles had license plates from the State of Mexico, which borders the capital, the spokesman added.

(Reporting By Cyntia Barrera Diaz; Editing by Vicki Allen and Eric Walsh)