U.S. President Barack Obama (left) speaks during a joint news conference with South Africa's President Jacob Zuma at the Union Buildings in Pretoria, South Africa, June 29, 2013. Jason Reed/Reuters

WASHINGTON (Reuters) -- U.S. President Barack Obama, in a phone call with South African President Jacob Zuma on Wednesday, expressed "deep concern" about the situation in Burundi, the White House said.

Obama asked Zuma "to continue to work with other regional actors to call for calm and press for a dialogue that can bring about a long-term solution to the crisis," the White House said in a statement.

At least 240 people have been killed and tens of thousands have fled to neighboring states, during months of violence that began when Burundi's president, Pierre Nkurunziza, decided in April to run for a third term. He won a disputed election in July.

(Reporting by Eric Beech; Editing by Mohammad Zargham)