Cyril Ramaphosa has become South Africa’s president a day after embattled leader Jacob Zuma resigned.
He was the only candidate nominated by the parliament, which is dominated by his African National Congress. MPs broke into song at the announcement.
In his first presidential speech Mr Ramaphosa, 65, said he would tackle the corruption which allegedly became widespread under Mr Zuma.
The ANC had told Mr Zuma, who faces numerous corruption allegations but denies any wrongdoing, to step down or face a vote of no-confidence.
One allegation was that he allowed the wealthy Gupta family, with whom he has personal ties, to wield influence over policy, in an example of “state capture”.
An arrest warrant has been issued for Ajay Gupta, one of the three most prominent Gupta brothers, officials said on Thursday.
This follows a raid by the Hawks, an elite police unit, on their home on Wednesday. The family has denied corruption allegations.
Mr Ramaphosa told parliament that corruption and state capture were “on our radar screen”.
He is due to deliver a State of the Nation address on Friday. This was delayed last week amid uncertainty about who should deliver it and Mr Zuma’s reluctance to step down.
The leader of the opposition, Mmusi Maimane of the Democratic Alliance, congratulated Mr Ramaphosa, but also urged the president to dissolve the assembly and call an election.
“We don’t have a Jacob Zuma problem, we have an ANC problem. And I want to say this, that this is a moment in our country where we must move section 50 and go back to the people of South Africa and ask them for a fresh mandate.”
Mr Maimane also encouraged the new president to purge the ANC of its corrupt members.
Another opposition party, the Economic Freedom Fighters, walked out of the parliamentary debate. It also wants new elections, rather than the ANC deciding on the identity of the new president.