Nigeria ? The ruling party’s hopes that a weekend election in Nigeria would be accepted as credible were dampened Sunday when local observers and the main opposition parties condemned what they said was vote-rigging and called for a repeat of the balloting.

The German presidency of the European Union issued a statement raising doubts on whether Saturday’s presidential and parliamentary elections were free and fair after EU observers expressed concern over irregularities.

One of the main presidential contenders, Vice President Alhaji Atiku Abubakar, said the balloting was a sham and called for the results to be quashed.

The elections were seen as a test of Nigeria’s development as a democracy, the first transfer from one civilian administration to another in a country ruled predominantly by the military since independence in 1960.

The voting was flawed by logistical problems, delays and violence in some areas, and followed state elections a week earlier that brought criticism from international and local observers.

The results of Saturday’s elections are due today.

Umaru Yar Adua, presidential candidate for the ruling People’s Democratic Party, is widely expected to be announced as the winner, given preliminary results released Sunday and the party’s strong showing in the state elections.