“I would like to thank you most sincerely for your kind and comradely message on the occasion of my 70th birthday,” he wrote.
“I would like to assure you that I will continue to try to do my best to pursue all… objectives as an activist for the renaissance of Africa, in keeping with the historic traditions of our movement, the ANC.”
The letter was posted on the African National Congress Youth League website.
The league said on Monday that Mbeki was committed to the development of the African continent.
“As president of the ANC… Mbeki has led the collective charge for the renewed development of the African continent, notably through the African Renaissance and the New Partnership for Africa’s Development (Nepad),” it said.
“We commend Cde Thabo Mbeki… and the role he continues to play towards the attainment of the Freedom Charter demand that ‘South Africa shall strive to maintain world peace and the settlement of all international disputes by negotiation – not war’.”
The ANCYL did not officially extend birthday wishes to President Jacob Zuma on his 70th birthday on April 12.
Mbeki was defeated by Zuma in the December 2007 leadership race in Polokwane, following intense campaigning for Zuma by the ANCYL.