ABUJA (Reuters) - The head of the European Union’s observer mission to Nigeria’s presidential and parliamentary elections said on Monday that the vote had been hit by operational shortcomings that made it difficult for voters.

“Serious operational shortcomings put undue burden on voters,” said Maria Arena, the EU’s chief observer and member of the European parliament told reporters.

Various election observers have said violence, delayed opening of polling centers and problems with electronic voting machines made it difficult for many to vote on Saturday and meant voting took place in a small number of places on Sunday.