Leader of South Africa's largest opposition party steps down

FILE - In this Thursday, Feb. 12, 2015 file photo Democratic Alliance leader, Helen Zille, arrives for the opening of Parliament in Cape Town, South Africa. Zille announced on Sunday, April 12, 2015 that she would not stand for re-election in the party's upcoming congress in May this year. (AP Photo/Schalk van Zuydam, File) (The Associated Press)

The leader of South Africa's largest opposition party has stepped down.

Democratic Alliance leader Helen Zille announced on Sunday that she would not stand for re-election in the party's upcoming congress in May this year.

In a statement, Zille said she her decision to step down two years earlier than she had originally planned was in the best interest of the party.

Zille said she would remain the premier of South Africa's Western Cape province.

The party's former parliamentary leader and a favorite to succeed Zille, Lindiwe Mazibuko, said in a statement on Monday that she would not run for the party's top seat. Mazibuko is in the United States, studying at Harvard University.

The Democratic Alliance won 22 percent in South Africa's 2014 national election.