"I will catch up. Tomorrow is Sunday," he told reporters when asked how much sleep did he have in the last two days.
76-year-old Ansari, who had returned to Delhi after a four-day visit to Uzbekistan in the evening of May 24, had left for the Ethiopian capital in the early hours of May 25.
He spent the entire Saturday attending various sessions at the Summit which he addressed and later joined the celebrations which went on till late in the night.
The Vice President said he had a "good meeting" with Ethiopian Prime Minister Hailemariam Desalegn, who is also Chairperson of the AU, on the sidelines of the Summit.
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He also interacted with Chairperson of AU Commission Nkosazana Diamini-Zuma.
India has been among the countries in the forefront of the transformation of African states and has said the 50th anniversary of the Union as a milestone in that endeavour.
Besides India, other select partners invited for the Summit of the top African leadership included the US, the European Union, France, Brazil, Russia, China, Jamaica, Palestine and the UAE.