Oil tankers loaded crude normally from Nigerian export terminals on Wednesday morning, the first day of a three-day strike by oil unions
to protest about violence against oil workers
, Rueters reported.
Thousands of union members stayed away from their workplaces in Africa
's top oil producer and queues formed at filling stations as Nigerians prepared for fuel shortages.
Nigeria is the world's eighth largest exporter of oil, shipping 2.4 million barrels a day to refineries in Europe, America and Asia.
Unions are trying to put pressure on the government to crack down on a growing wave of attacks against oil workers by militants and criminals in the Niger Delta, a vast wetlands that is home to Africa's largest oil industry.