President Robert Mugabe has threatened to expel the US ambassador, criticizing him for advice he has given Mugabe's opponent in a presidential runoff. Mugabe, speaking Sunday at the formal launch of his election campaign, noted 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. Mugabe says that, if McGee continues offering advice to Tsvangirai, he will "kick him out of the country." Mugabe also ridiculed claims the opposition leader was the target of a military assassination plot.