PRETORIA, South Africa -- The Zimbabwean opposition leader won his nation's disputed presidential election, the top U.S. envoy to Africa said Thursday.

Assistant U.S. Secretary of State for African Affairs Jendayi Frazer said that Morgan Tsvangirai won the March 29 presidential race, and that therefore no power-sharing arrangement was needed with longtime President Robert Mugabe.

"We think in this situation we have a clear victor," she told reporters. "Morgan Tsvangirai won and perhaps outright, at which point you don't need a government of national unity. You have to accept the result."

But she added: "There may need to be a political solution, a negotiated solution."

Frazer was speaking in South Africa at the start of a visit to bolster international pressure on Zimbabwe's government. The U.S. has long been among Mugabe's sharpest critics.

The opposition has claimed that its leader Tsvangirai beat Mugabe outright. Independent Zimbabwean observers also say Tsvangirai won, though not by enough to avoid a runoff.
Frazer said she was basing her conclusions on that independent tally.

Meanwhile, Zimbabweans are still awaiting the results, with the opposition accusing Mugabe of withholding them while he plots how to keep power. Mugabe, 82, has led Zimbabwe since independence in 1980.