(CNN) -- Skulls taken by German scientists over a century ago have been returned to Namibia amid jubilant scenes and celebrations.
Thousands flocked to Namibia's Hosea Kutako International Airport Tuesday, praying, singing, and chanting as the 20 skulls were returned to their homeland.
The skulls, which were transported in caskets draped with the Namibian flag, were removed from the plane with military honors.
Among those welcoming the skulls was the country's Prime Minister Nahas Angula who said, "These mortal remains are testimony to the horrors of colonialism and German cruelty against our people. May the mortal remains of our ancestors proceed into their homeland," Namibian media reported.
According to historians, the skulls were taken during the bloody 1904 -1908 colonial conflict in former German West-South Africa, when the Herero tribe rebelled against German colonial forces. It's estimated that thousands were killed in the uprising. Once in Berlin, the skulls were used in research in an attempt to prove the supposed racial supremacy of European whites.
The skulls were rediscovered at Berlin's Charite University Hospital in 2005 and are believed to belong to Namibia's Nama and Herero ethnic peoples. They consist of 15 males, including a three-year-old boy and four females, said Charite spokeswoman Claudia Peter.
A delegation of over 50 Namibians traveled last week to Berlin for a handover ceremony before the skulls were repatriated to Namibia. Members of the delegation read a prayer outside the hospital before the ceremony.
The skulls have reignited old political tensions between the two countries.
The Namibian government has, for a number of years, demanded Germany acknowledge the war as genocide, calling for an apology as well as reparations.
The German government, which gives development aid to Namibia has refused to pay reparations. It has, however, expressed regret for the incident. A statement issued by German Deputy Foreign Minister, Cornelia Pieper last month read, "We Germans acknowledge and accept this heavy legacy and the ensuing moral and historical responsibility to Namibia.
"The German Government is fulfilling this duty through particularly close bilateral cooperation - and development cooperation - with Namibia," it continued.
Pieper added, "I would also like to express my own personal deep regret and shame for what was done to the ancestors of the tribal representatives now in Berlin."
For his part, the CEO of Charite University Hospital, Professor Karl Max Einhaupl, apologized to the Namibian delegation present at the ceremony in Berlin for the role played by German scientists.
"With this step we face up to an inglorious chapter of German history," he said. "As a medical doctor and scientist myself, it is especially painful for me to realize that even physicians worked in the service of this early form of racism."
Peter said historians now agree that much of the research undertaken by these early scientists was a precursor to Nazi ideology and is now universally acknowledged as a "perverse" science.
Despite years of research little is known about how the 20 people died, said Peter.
"Their cause of death could not be determined. Three skulls showed signs of lack of nutrition, but there was no sign of a violent death," she said.
But, she stated, this did not rule out the possibility the skulls belonged to victims of the conflict, with many thousands of people dying of starvation and exhaustion in camps set up by German colonial forces.