Four Vietnamese soldiers were killed and nine others wounded in an explosion during a training exercise, a local official said on Tuesday.
The incident happened Monday at the Chi Lang firing range in Tinh Bien, a district in the southern province of An Giang, the Ho Chi Minh City Law newspaper reported, without giving details on the cause.
The head of Tinh Bien's local government, Nguyen Van Con, confirmed the report but declined to give further details. He said the case is under investigation.
Communist Vietnam is seeking to modernise its military hardware, much of which is antiquated.