[JURIST] The two major opposition parties in Nigeria [JURIST news archive] and an election watch group on Sunday challenged the legitimacy of the country's Saturday presidential elections, reporting voting delays and potential ballot-rigging in favor of the People's Democratic Party (PDP) [BBC backgrounder], party of outgoing Nigerian President Olusegun Obasanjo [BBC profile], in a contest that appeared to draw a low voter turnout. The Transition Monitoring Group [Reuters report], an internationally-funded independent watch group deploying 50,000 observers, said that many polls opened late, and that "no election was held at all" in some of Nigeria's 36 states, particularly in the southeast. The group called for cancellation of the results. Opposition parties All Nigeria People's Party and Action Congress [INEC profiles], each of which ran a major contender in the presidential election, denounced the proceedings but declined to reject the vote outright until after the results are announced. Party members pointed to ballot shortages in opposition strongholds and to voter intimidation as evidence of the PDP's attempts at fraud. A spokesman for Action Congress, the party of embattled candidate and current Vice President Atiku Abubakar [official website; JURIST news archive], said the party would challenge any corrupt results in court.

Independent Nigerian Electoral Commission (INEC) [official website] Chairman Maurice Iwu defended the election, saying it had "gone smoothly, despite some problems." Ballots were printed without serial numbers after the last-minute addition of Abubakar, who was cleared by the Supreme Court to run for president last week despite charges of corruption [JURIST reports]. Opposition members said the lack of unique ballot markings increased the possibility for fraud; INEC has pledged to cancel any results whose integrity is in doubt [INEC report]. Despite the high tensions, there was little evidence of the violence which marred the April 14 state elections [JURIST report], where as many as 50 were killed. Nigerian newspaper Vanguard reported [text] that sixteen police officers were killed in separate accidents, and that a failed attempt was made to drive a truck bomb into the electoral commission headquarters. Election results are expected late Monday. The winner, who must win the popular vote as well as at least a quarter of the votes cast in 24 states or face a runoff, will take office May 29. AP has more.