The event took place in Nuremberg, Germany.
Omo-Agege made condemnation in a statement by his Special Adviser on Media and Publicity, Mr Yomi Odunuga in Abuja on Sunday.
He said the dastardly act was not only an exportation of irrationality, but also an international affront against the image of the Igbos and Nigeria in general.
He expressed shock over the undeserved assault and called on law enforcement agencies in Germany to investigate and bring to book the perpetrators of the attack.
He said: “Sen. Ekweremadu honoured the invitation of patriotic Igbos in Germany who wanted him to deliver a keynote address at the event organised to commemorate the new yam festival.
“But some aggressively discourteous elements hijacked the effort to perpetrate a disgraceful assault that seeks to deepen the portrayal of members of the IPOB as enemies of democratic norms and values.
“What they did is not only a violent assault against the good image of the Igbo race across the world.
“It is also an aggressive attack against the traditional norms of a people known to be hardworking and respectful of meaningful contributions by leaders such as sen. Ekweremadu.
“Such disappointing physical abuse also grossly disregards Ekweremadu’s democratic antecedents and his long-standing commitment to the cause of his people.
“Such criminal attack along with other anti-social attempt, to accuse, condemn and lynch anyone remains utterly condemnable and illegal.”
Omo -Agege said it was notwithstanding whether the attack took place on Nigerian or foreign soil, it was the “easiest invitation to anomie.