Worshippers have been targeted by police, the archbishops say
Two of the most senior figures in the Anglican Church have issued a powerful challenge to UN Secretary General Ban Ki-moon to intervene in Zimbabwe.
The archbishops of Canterbury and Cape Town accused Zimbabwe's security forces of targeting church-goers in a violent campaign against the opposition.
The call came as opposition leader Morgan Tsvangirai launched his campaign for a presidential run-off on 27 June.
He accused President Robert Mugabe of reducing the country to "despair".
He said his rival was to blame for giving Zimbabwe the highest inflation in the world and one of the worst education systems.
"The state of our nation today is a state of despair," he said.
The Movement for Democratic Change (MDC) leader said that he the campaign of violence must stop.
"There will be no tolerance or amnesty for those who continue to injure, rape and murder our citizens," he told an audience in the capital, Harare.
"We consider these acts as criminal acts, not political acts."
In a statement, Archbishop of Canterbury Rowan Williams, and the Archbishop of Cape Town, Thabo Makgoba, said there was a sharp escalation of violence two weeks ago when police and security forces disrupted Sunday services and beat worshipers.
In one case, they beat women as they knelt in front of the altar in the act of taking the bread and wine of the communion service.
"We are concerned to know what the UN Security Council... is doing to defend Mothers' Union meetings at churches and prevent people being torn away from altar rails on the orders of ruling party or state official," the statement said.
"We plead once more for immediate high level Sadc [Southern African Development Community] and UN mediation and monitoring to ensure a free and fair presidential run-off, and the protection of its citizens from state-organised violence."
The BBC's religious affairs correspondent Robert Pigott says Anglicans have been targeted since the Church replaced former Bishop Nolbert Kunonga, who was a strong supporter of President Mugabe.
Since then, the deposed bishop has been able to prevent Anglicans getting into the cathedral.
Dr Williams said: "There is a continuing failure to enforce court orders permitting Anglicans to worship in their cathedral church in Harare and other parishes."
Our correspondent says other Anglican leaders have gone on record demanding that the international community take responsibility for dealing with the violence and intimidation in Zimbabwe.
Several Anglican leaders have been outspoken on Zimbabwe
The Archbishop of York, John Sentamu, once a refugee from Idi Amin's Uganda, last year cut up his clerical collar live on BBC television, promising to go without one until Mr Mugabe had gone.
He issued a joint statement with Dr Williams last month calling on Zimbabwe's neighbours to act far more robustly to avert a "spiral of communal violence".
Dr Sentamu said on that occasion: "I didn't believe the softy-softly approach of [South African President] Thabo Mbeki would work.
"I think it's time we acknowledged that African countries are sometimes incapable of creating good governance on their own.
"We must stop saying this is just an African problem... this is an international problem."
Our reporter says that the head of the Anglican Communion is telling the UN Security Council that someone must take responsibility for Zimbabwe, that doing nothing is not enough and the ball is now in the UN's court.