Article 17
1. When completing customs formalities for the export of firearms, their parts and essential components or ammunition at the customs office of export, the exporter shall furnish proof that any necessary export authorisation has been obtained. 2. The exporter may be required to provide a translation into an official language of the Member State where the export declaration is presented of any documents furnished as proof. 3. Without prejudice to any powers conferred on them under Regulation (EEC) No 2913/92, Member States shall, for a period not exceeding 10 days, suspend the process of export from their territory or, if necessary, otherwise prevent firearms, their parts and essential components or ammunition which are covered by a valid export authorisation from leaving the customs territory of the Union through their territory, where they have grounds for suspicion that: (a) relevant information was not taken into account when the authorisation was granted; or (b) circumstances have materially changed since the authorisation was granted. In exceptional circumstances and for duly substantiated reasons, that period may be extended to 30 days. 4. Within the period or extended period referred to in paragraph 3, Member States shall either release the firearms, their parts and essential components or ammunition, or take action pursuant to Article 11(1)(b).