The Nigerian Supreme Court has adjourned without ruling on a challenge to the validity of the 2007 presidential election that brought President Umaru Yar'Adua to power.

After a hearing Thursday, Supreme Court Chief Justice Idris Kutigi announced the court's judgment was reserved - meaning the court will rule at a later date.

He adjourned the court without setting a date for the decision.

The challenge to the election was brought by two opposition candidates - Nigeria's former military ruler General Muhammadu Buhari and former Vice President Atiku Abubakar. The two men are seeking to nullify the vote.

Local and international observers have described Nigeria's April 2007 elections as deeply flawed because of widespread intimidation, disorganization and fraud.

In the 18 months since the polls, Nigerian courts have overturned the results of at least 11 state governors' elections.

At his inauguration last year, President Yar'Adua acknowledged there were "lapses and shortcomings" in the elections, and he promised to address the controversy.

Some information for this report was provided by AFP and Reuters.