Mugabe says Ambassador James McGee publicly urged opposition leader Morgan Tsvangirai to return to Zimbabwe to start contesting the run-off presidential run-off election.
"When the American ambassador said come back to Morgan he came back frog jumping," Mugabe said.
Tsvangirai returned from self-imposed exile in Botswana and South Africa on Saturday after more than six weeks abroad.
President Mugabe says that if McGee continues offering advice to Tsvangirai, he will kick McGee out of the country.
Speaking on Sunday at the formal launch of his election campaign, the president also ridiculed claims the opposition leader was the target of a military assassination plot.
"Tsvangirai is running around telling people I want to kill him," Mugabe said. "I don't even have a bow and arrow."
Despite fears of an assassination plot and the threat of treason charges, Tsvangirai returned to Zimbabwe looking relaxed and launched into a blistering attack on President Mugabe.
The president also called on the ruling Zanu PF to bury differences until ‘the war’ with the West is over. "It's a war to defend our sovereignty. We have to bury our differences in Zanu-PF until the war with foreigners is over," he said. “We have an enemy who wants us to go back to be ruled by the whites.”
He added: “What we know is a family is having problems and we should unite as a family against outsiders. Some of you want to sell your country for candy, like children. Disunity, that's what is killing us.”
Referring to defectors from the Zanu PF party, he said: "Where are they going? Away from the revolution to where?"
He also reiterated claims that the opposition were organising the violence in the country, saying his supporters should refrain from attacking but could defend themselves.
"We say we don't want violence at all, but that does not mean if someone confronts you with a spear you fold your arms and say 'my president says no to violence'. I'm not saying don't defend yourself."
He also said MDC-T leader was trying to reverse the gains made at independence in April 1980 and said Tsvangirai had made promises to white commercial farmers that he would reverse the farm acquisitions. He said the commercial farmers had taken to the streets when MDC-T Secretary General Tendai Biti announced that Morgan Tsvangirai had won the election.
“You saw the joy the British had, the Americans had, you saw them celebrating as if Zimbabweans are an extension of Britain and America.”
Mugabe also said the State Department's top diplomat for Africa, Jendayi Frazer, behaved like a prostitute for suggesting that Zimbabwe's opposition Movement for Democratic Change and its leader Morgan Tsvangirai had won the March 29 elections.
“You saw this little American girl trotting around like a prostitute celebrating that the MDC had won. A disgraceful act,” Mugabe said.
President Mugabe also said that Zimbabweans living in South Africa would be given land if they returned home.
"We have land for our people in South Africa who may want to return home," he said in reference to Zimbabweans who are among the African migrants targeted in a wave of deadly xenophobic attacks in South Africa.
