Rice, in the Mideast for peace talks, made the harsh comments after balloting Saturday in Zimbabwe that presented Robert Mugabe with the toughest challenge to his 28-year rule. The main opposition party on Sunday claimed an early lead; preliminary results were expected by Monday.
"We've made very clear our concerns about how this election might be conducted, given the very bad record of Mugabe concerning his people, the opposition and the region," Rice told reporters after meeting with Israeli and Palestinian leaders.
"We've tried to make a case ... that there needed to be free and fair elections in Zimbabwe as much as it was possible. It's difficult since really no international observation was allowed," the top U.S. diplomat said.
"But really, the Mugabe regime is a disgrace to the people of Zimbabwe and a disgrace to southern Africa and to the continent of Africa as whole," she said.
Zimbabwe had barred observers traveling from the United States and the European Union and several international media organizations. The State Department said Friday the U.S. would field almost a dozen poll watchers for the elections and would report afterward on the electoral process and the results.
The department, in its annual accounting of human rights practices around the world, listed Zimbabwe this month as among abusers of human rights.
In January, the Bush administration imposed financial penalties on Zimbabwe's intelligence chief, Mugabe's nephew, as well as two companies accused of undermining democracy in the southern African country.
It was the government's latest move to apply more financial pressure on Mugabe, who over the years has become increasingly authoritarian, spearheading media control and takeovers of white-owned farms.