Retired archbishop Desmond Tutu was admitted into a hospital in Cape Town for treatment of an infection, the Desmond and Leah Tutu Legacy Foundation said.

The foundation added that doctors are performing tests on the Nobel Peace Prize laureate to uncover the cause of a persistent infection.

Tutu spent Wednesday morning working from his office before being admitted to the hospital. The 81-year-old will receive non-surgical treatment that will be ongoing for five days.

"He was in good spirits and full of praise for the care he receives from an exceptional team of doctors," the foundation said in a statement.

Just a few weeks ago, Tutu was awarded the 2013 Templeton Prize with a $1.7 million award. The award was given by the John Templeton Foundation for Tutu's "spiritual progress."

"By embracing such universal concepts of the image of God within each person, Desmond Tutu also demonstrates how the innate humanity within each of us is intrinsically tied to the humanity between all peoples," Templeton said in a video. "Desmond Tutu calls upon all of us to recognize that each and every human being is unique in all of history and, in doing so, to embrace our own vast potential to be agents for spiritual progress and positive change. Not only does he teach this idea, he lives it."

Tutu was known as an outspoken crusader against apartheid in South Africa beginning in the 1970s, while he was the bishop of the Anglican Church in Lesotho and general secretary of the South African Council of Churches. The government enforced apartheid that suppressed blacks. Apartheid ended in the 1990s while he chaired the Truth and Reconciliation Commission, which voiced the concerns of both supporters and reformers of apartheid and granted amnesty to perpetrators of crimes against human rights.

In 1984 he was the first South African to receive the Nobel Peace Prize since Albert Luthuli in 1961, who also fought against apartheid.

Tutu withdrew from the public sphere in 2011 to enter retirement. He returned to give a commencement speech to students at the Gonzaga University in Washington in May 2012.