Washington: A US official says the state department intends to designate a Nigerian Islamist militant group as a foreign terrorist organization on Wednesday. Designating the group called Boko Haram, which wants to impose Islamic law across northern Nigeria, means that US regulatory agencies are instructed to block business and financial transactions with the organization. Boko Haram, which has been blamed for thousands of deaths in the past four years, and other splinter Islamist groups are seen as the biggest security threat in Nigeria, Africa's most populous country and top oil exporter. The official spoke on condition of anonymity because the announcement has not yet been made.