The authorities in Guinea Bissau have suspended the army chief-of-staff, Brigadier-General Ansoumane Mane.
The suspension follows the arrest of several military officers for allegedly smuggling arms to separatist rebels across the border in southern Senegal.
The arrests were ordered by the Defence Minister, Samba Lamine Mane.
In an interview with the BBC, he said the army commander must take responsibility for the trafficking of the weapons.
A correspondent for the BBC in Senegal says there have been persistent rumours that Senegalese rebels were receiving help from the army in Guinea Bissau, but this is the first official confirmation.
Our correspondent says there is considerable sympathy within Guinea Bissau for the Casamance rebels who helped Bissau nationalists in their war of independence from Portuguese colonial rule.
From the newsroom of the BBC World Service