Witnesses say Zimbabwe President Robert Mugabe, 90, fell down steps from a podium after speaking to supporters.

Several witnesses, who insisted on anonymity because of security concerns, said Mugabe appeared to miss a step and toppled when he left the raised lectern at the airport Wednesday afternoon upon his return from Ethiopia.

They said his aides quickly helped him up and escorted him to his limousine which sped away.

Some press photographers who captured the fall said they were forced to delete their pictures by security personnel.

Mugabe was elected chairman of the 54-nation African Union at a summit of African leaders in Addis Ababa, Ethiopia. He celebrates his 91st birthday on February 21. His spokesman was not immediately available for comment.