JOHANNESBURG — South Africa’s long-governing African National Congress party appeared headed for a victory in national elections, partial results showed on Thursday, though its support seemed to have dipped under the leadership of President Cyril Ramaphosa.

[Here are the latest results, on Friday.]

The party led with 57 percent of the vote on Thursday evening, with ballots for the national Parliament and provincial legislatures counted in about 65 percent of polling stations nationwide.

The government’s Council for Scientific and Industrial Research and some local news organizations projected that the A.N.C. would end up with less than 60 percent of the vote — a symbolically important threshold that the party has not failed to cross since coming to power in 1994 at the end of apartheid.