(CNN) At least 21 people were killed Saturday when a bus and truck crashed in Guatemala, the Guatemalan Public Ministry said.

At least seven children were among the dead and 11 people were injured, according to a statement from the Public Ministry

The crash occurred near the town of Gualán in the department of Zacapa, the statement said, about 168 kilometers (104 miles) from the nation's capital, Guatemala City.

It's unclear what caused the crash. The drivers of the bus and the truck were detained and sent to a detention center, the ministry said.

Investigators are still working to identify some of the victims.

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