Crowds cheer as Jacob Zuma is sworn in
Jacob Zuma, leader of the African National Congress, has been sworn in as South Africa's new president.
He took the oath in front of 5,000 invited guests and crowds of supporters who had gathered at the Union Buildings in Pretoria for the ceremony.
In a speech, he described it as a "moment of renewal" for South Africa, and vowed to work for reconciliation.
Correspondents described a festive atmosphere in the capital that was not dampened by earlier rain and cold.
Mr Zuma, 67, is expected to bring a populist touch, ensuring a very different presidency to that of Thabo Mbeki.
But his first speech as president was measured and statesmanlike, not intended to whip up the crowds into a frenzy as he often does, the BBC's Joseph Winter in Pretoria says.
In his speech, Mr Zuma praised his predecessors and said he would follow the policies of reconciliation between the races that Nelson Mandela had pursued.
This was a "moment of renewal", he said, and "an opportunity to discover that which binds us together as a nation".
Joseph Winter, Reporting from Pretoria
Jacob Zuma's first speech as president was statesmanlike, not intended to whip up the crowds.
There were cheers when he vowed to "not rest" in tackling the problems facing the country- although the loudest cheers came when he mentioned hosting the 2010 football World Cup.
After addressing the dignitaries, Mr Zuma came down to the lawns to speak to his supporters.
He received a rapturous welcome, but remained in presidential mode. He did not sing his customary song.
But his supporters were not disappointed. Their hero is president, bearing their hopes on his shoulders.
He acknowledged the country faced difficult economic times, but said "the foundations of our economy are strong and we need to continue to build on them" by working harder than ever.
He promised South Africans that he would devote himself to helping them improve their lives.
"I commit myself to the service of our nation with dedication, commitment, discipline, integrity, hard work and passion," he said.
Former Presidents Nelson Mandela and Thabo Mbeki were among those at the ceremony to witness Jacob Zuma become South Africa's fourth president since apartheid ended 15 years ago.
Mr Zuma, an unashamed polygamist, was accompanied by his senior wife Sizakele Khumalo on stage, although his other two current wives were present at the ceremony.
After taking his presidential oath, a Zulu praise dancer took to the stage, followed by a military fly-past and a 21-gun salute.
At least 30,000 supporters watched the ceremony on giant screens from lawns below the Union Buildings, the president's office.
They had been gathering there since before dawn, excited to be watching Mr Zuma become president.
"We are rejoicing. He's the people's leader," Nkompela Xolile told the BBC. "He knows the poor of this country."
Even an earlier torrential downpour did not dampen spirits - in Zulu tradition, rain during an important event is a good sign.
After his speech before dignitaries, President Zuma went down to the stage on the lawns below. In Zulu, he thanked the crowds for their support and spoke of the importance of unity in the country.
Jacob Zuma's journey to the Union Buildings has been an epic struggle, the BBC's South Africa correspondent Peter Biles says.
He was sacked as vice-president by Thabo Mbeki four years ago after being implicated in a corruption scandal - allegations Mr Zuma always denied.
Earlier rain failed to dampen the spirits of Zuma supporters
The case was eventually thrown out amid evidence of government meddling in the investigation.
In February 2006, he was acquitted of rape in a separate case, though he was widely criticised for his comments about sex and HIV/Aids.
At the time, few observers believed Mr Zuma could remain a serious contender for president, our correspondent says.
But he fought to clear his name, retained enormous popularity, especially among his fellow Zulus, and led the ANC to a convincing election victory two weeks ago on a pro-poor populist ticket.
He was officially elected president by members of parliament on Wednesday, and is due unveil his new cabinet on Sunday.
Mr Zuma has listed his five priorities as land redistribution, education, health, lowering crime levels and finding decent work for all South Africans.
He has promised a more hands-on approach and to work more closely with the opposition.