ABUJA, May 17 (Reuters) - Nigerian unions called for a two-day strike on May 28-29 to protest against widespread vote-rigging in last month's elections, the secretary general of the Trade Union Congress told Reuters on Thursday. John Kolawale said the strike, which will coincide with the inauguration of president-elect Umaru Yar'Adua on May 29, would not affect oil production. Nigeria is the world's eighth-biggest exporter of crude.
