Rules of origin: claimants must declare origin and produce Certificate of Origin, subject to verification and denial grounds. To claim preferential tariff, an importer must declare goods as originating, produce a Certificate of Origin for each item, record CoO details in the bill of entry and indicate accumulation/cumulation or direct transport where applicable; importers must retain basic origin information for inquiry. Customs may seek verification from the partner country when CoO genuineness is doubtful, origin criteria appear unmet, or random checks are undertaken, with prescribed timelines for response. Preferential treatment may be denied without verification if the tariff item is ineligible, the CoO description is incomplete, the CoO is altered without authentication, or is produced after expiry.