HARARE, Zimbabwe - President Robert Mugabe threatened yesterday to expel the U.S. ambassador for providing advice to the opposition candidate in the forthcoming presidential runoff.

Mugabe, speaking at the formal launch of his campaign for the June 27 runoff, said Ambassador James McGee had publicly urged opposition leader Morgan Tsvangirai to return to Zimbabwe to lead his embattled supporters. Tsvangirai returned Saturday after more than six weeks abroad.

"As long as he carries on doing that, I will kick him out of the country," Mugabe said of McGee, a Vietnam War veteran. "I don't care if he fought in Vietnam. This is Zimbabwe, not an extension of America."

Mugabe 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."

Independent human rights groups, McGee and other diplomats say opposition supporters have been beaten and killed by government and ruling party thugs to ensure the 84-year-old Mugabe, in power since independence from Britain in 1980, wins the runoff. Mugabe trailed Tsvangirai in the first round on March 29.

Tsvangirai left soon after the first vote to warn the world about impending violence. He first tried to return May 17, but canceled the trip after his party said he was the target of a military assassination plot. Tsvangirai has survived at least three attempts on his life.

"For too long, Zimbabwe has been isolated, first from the international community and now from the African community, due to the policies of intolerance and repression imposed upon us by Robert Mugabe," Tsvangirai said in a statement yesterday. "For too, long we have suffered under the burden of economic hardship and poverty as a result of misguided policies."

Yesterday, Mugabe returned to his theme of portraying Tsvangirai as a stooge of the West, charges the opposition rejects.

"We have an enemy who wants us to go back to be ruled by the whites," Mugabe said.

He claimed former colonial ruler Britain and the United States had celebrated the opposition's showing in the initial round of voting. In addition to Tsvangirai coming first in a field of four in the presidential race, his Movement for Democratic Change won control of parliament - the first time Mugabe's ZANU-PF lost parliament since independence.

"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 said yesterday.