Egyptian President Hosni Mubarak is not attending the African Union summit in the Ugandan capital, Kampala.
State media said Mr Mubarak had delegated Prime Minister Ahmed Nazif.
There has been speculation about the health of the 82-year-old leader, but officials say he is in good condition.
Mr Mubarak has been absent from most AU meetings since 1995. However media reports in both Egypt and Uganda had suggested he was expected to attend the Kampala summit.
This had not been confirmed by Egyptian officials.
On Thursday, the president addressed the nation on the eve of Egypt's annual Revolution Day, commemorating the anniversary of the military coup that toppled the monarchy in 1952.
The BBC's Jon Leyne in Cairo said Mr Mubarak appeared healthy but thinner than usual, and spoke standing up for more than 10 minutes.
Mr Mubarak had gall bladder surgery in Germany in March.
Concerns about his health resurfaced when a series of meetings was postponed last week.
But Mr Mubarak has since followed a busy schedule, attending public events almost daily.
Correspondents say Mr Mubarak's health is a taboo topic in Egypt and a cause of political and economic uncertainty, because he has no obvious successor.
Mr Mubarak has been in power for 29 years and his fifth six-year term ends in 2011. However, he has not made it clear whether he intends to stand in the elections.