Johannesburg - Former UN secretary general Kofi Annan, former US president Jimmy Carter and Mozambican activist Graca Machel have had to call off a trip to Zimbabwe after President Robert Mugabe refused them entry, they announced in Johannesburg Saturday.

Addressing a press conference, the three, who were due to travel to Zimbabwe Saturday on behalf of The Elders grouping of leading statesmen and women, said they were disappointed that they had been denied an opportunity to shine a light on the humanitarian crisis in the country.

South African President Kgalema Motlanthe and ex-president Thabo Mbeki, who is mediating in Zimbabwe's power-sharing talks, had intervened on their behalf with Mugabe, but to no avail, they said.

"It seems obvious to me that the leaders of the (Mugabe) government are very immune to reaching out for help for their people," Carter said.

Machel, who is the wife of The Elders convener, anti-apartheid icon Nelson Mandela, also said she was "extremely disappointed."

This is the first time The Elders, which was founded in 2007 to tackle conflicts around the world and includes several Nobel Peace Prize winners, including South African Archbishop Desmond Tutu, has been refused entry to a country. Carter visited Sudan earlier this year.

State media in Zimbabwe Thursday quoted a government source denigrating The Elders visit as a "rescue package" for the opposition Movement for Democratic Change. (dpa)