Johannesburg  - Zambian President Levy Mwanawasa, a vocal critic of Zimbabwe leader Robert Mugabe, collapsed Monday an the fringe of the African Union summit in Egypt, South African television reported.

The 59-year-old was admitted to the intensive care unit of a hospital in the summit resort of Sharm el-Sheikh, the report by the South African Broadcasting Corporation said.

Mwanawasa had complained of chest pains shortly before he collapsed. Doctors said he suffered a heart attack, according to SABC.

The president, who has been in power since 2002, was treated two years ago for a heart condition.

At the summit, Mugabe faced his critics over Sunday's controversial one-man presidential election which saw him returned to power after opposition leader Morgan Tsvangirai pulled out, citing state-sponsored violence against his supporters. (dpa)