President Robert Mugabe on Friday ordered police to be deployed "fully armed" to deal forcefully with unrest in Harare, the capital. He also threatened to expel Western diplomats who showed support for the opposition Movement for Democratic Change.

Mugabe, whose comments were reported on state radio, heightened tension at the end of a week in which police dealt brutally with protests against his regime, inflicting serious injuries on Morgan Tsvangirai, the MDC leader.

It was an open challenge to opposition politicians who earlier agreed to set aside 18 months of infighting, which had left their parties bitterly divided, to challenge Mugabe.

• Click here for FOXNews.com's Africa Center.

Political and civil leaders, some of whom bore the scars of savage beatings inflicted by the president's security forces, stood together on a podium to mark what they said was "the final stage of the final push" to force him out of office.

"Sunday was the demonstration of commitment to working together; there is no better place to demonstrate unity than in the battlefield," said Arthur Mutambara, the leader of a breakaway faction of the MDC.

There were loud cheers when Mutambara declared: "We have our differences but we will manage them. Arthur Mutambara will not stand in an election against Morgan Tsvangirai; Morgan Tsvangirai will not stand against Arthur Mutambara."

"I hope, Robert Mugabe, you sick old man, you are listening," he said.

Tsvangirai, who suffered a severe head injury when security forces broke up Sunday's opposition rally, was unable to attend yesterday's act of reconciliation because of his injuries, although he was later released from hospital in a wheelchair.

However, Tendai Biti, his secretary-general, sitting next to Mr Mutambara, endorsed the statement.

The MDC break-up in 2005 was "tragic," he said. "We have been seeing [in recent weeks] beginning to emerge the unity of opposition. This is the endgame."

Mutambara said: "We are in the final stages of the final push. We are going to do it by democratic means, by being arrested, beaten, but we are going to do it. We are continuing with defiance in spite of what Robert Mugabe says. We are talking about rebellion; war."

Asked whether this meant setting aside the MDC's long commitment to nonviolence, he said: "You can do your own interpretation. Mugabe is fighting against his own people. That is war against the people. Already there is violence."

Mugabe, 83, who has been in power for 27 years since Zimbabwe's independence from Britain, appeared to be preparing for further confrontations when he gave orders for police to carry guns.

A curfew is being enforced in some parts of Harare between 8 p.m. and dawn.

On Friday there were reports that the unrest had spread to Bulawayo, Zimbabwe's second city, where police reported an attempt to sabotage a railway line, and said that youths had set up roadblocks in townships.

Earlier this week a defiant Mugabe said that critics in the West could "go hang" in the face of strong international condemnation of his violent treatment of opposition protestors.

On Friday he gave a warning to Western diplomats not to intervene in Zimbabwe's domestic affairs or risk expulsion.

His comments are believed to refer to Andrew Pocock, the British ambassador in Harare, and Thomas Dell, the U.S. ambassador.

Britain on Friday called for a briefing of the U.N. Security Council on "the appalling events" in Zimbabwe.

Emyr Jones Parry, Britain's Ambassador to the U.N., said that Britain would also raise the crackdown on the Zimbabwe Opposition before the Human Rights Council in Geneva.

Archbishop Desmond Tutu, the South African Nobel laureate, said that African leaders should feel ashamed for their silence on this week's violence in Zimbabwe.

"We Africans should hang our heads in shame," said Archbishop Tutu. "How can what is happening in Zimbabwe elicit hardly a word of concern, let alone condemnation, from us leaders of Africa?