Zimbabwe's opposition movement healed long-standing divisions and declared that it has won control of Parliament for the first time in history ― and that President Robert Mugabe must concede defeat.

They also appealed to the U.N. Security Council to send a special envoy to Zimbabwe and to warn Mugabe that the mounting violence against opposition supporters was tantamount to "crimes against humanity."

Putting months of bickering behind them, Movement for Democratic Change leaders Morgan Tsvangirai and Arthur Mutambara stood united to order Mugabe to step aside.

"Old man, go and have an honorable exit," Tsvangirai said in a message April 28 to the 84-year-old autocrat who has ruled since independence from Britain in 1980.