(CNN) -- Zimbabwe President Robert Mugabe has warned against outside influences in next month's run-off election, likening one American diplomat to a "prostitute" and threatening to oust another from his country.

Robert Mugabe tries to stir voters with a blistering speech criticizing the U.S. and Britain.

"Zimbabwe cannot be British, it cannot be American. Yes, it is African," said Mugabe, whose speech Sunday was quoted Monday in The Herald, the state-run newspaper.

"You saw the joy that the British had, that the Americans had, and saw them here through their representatives celebrating and acting as if we Zimbabwe are either an extension of Britain or ... America. You saw that little American girl [U. S. Assistant Secretary of State for African Affairs Jendayi Frazer] trotting around the globe like a prostitute..."

Mugabe went on to say that U.S. Ambassador to Zimbabwe James McGee would be expelled from the country if he "persisted in meddling in Zimbabwe's electoral process," the newspaper reported.

The fallout from Zimbabwe's stalled election has brought international criticism, with Frazer taking the most emphatic stance. In April, Frazer accused Mugabe, who has ruled Zimbabwe for nearly three decades, of "trying to steal the election" and "intimidating the population and election officials as well."

The first election was March 29. An announcement of the winner of the presidential election was delayed for weeks as opposition leader Morgan Tsvangirai claimed he had won. The Zimbabwe Electoral Commission, after a long delay, ruled that neither candidate had won the required majority of votes, and scheduled a runoff election for June 27.

Since the March balloting, there have been numerous reports from Tsvangirai's party and church groups about kidnappings, torture and other violence, including the deaths of opposition party members. They say the violence targets opponents of Mugabe and his Zanu-PF party.

At about the same time Sunday that Mugabe was giving his campaign speech, Tsvangirai was speaking at a funeral.

Tsvangirai spoke harshly as he stood near the casket of a man he claimed was killed by Mugabe's supporters. Watch Tsvangirai address mourners »

"This is a clear testimony of the callousness of this regime," said Tsvangirai to a funeral procession of hundreds gathered outside the capital city of Harare. "They can kill us. They can maim us. But we are going on the 27th of June, our hearts dripping with blood, to vote him out of office."

Mugabe denies his supporters were responsible for election-related violence.

All About Zimbabwe • Robert Mugabe • Morgan Tsvangirai