"The deteriorating situation in Zimbabwe is a further illustration of the mis-rule of Zimbabwe’s rogue government," he said, as Mugabe threatened fresh elections in a bid to force through a stalled power-sharing deal.
Earlier on the United States said on Friday that President Robert Mugabe’s departure from office was long overdue and a food crisis and cholera epidemic in Zimbabwe meant it was now vital for the international community to act.
Zimbabwe has declared an emergency and appealed for international help to battle a cholera outbreak that has killed 575 people, with 12,700 reported cases of the disease, according to the United Nations.
"It’s well past time for Robert Mugabe to leave," U.S. Secretary of State Condoleezza Rice said in Copenhagen.
In a further sign of growing international pressure on Zimbabwe, European Union diplomats said the bloc planned more sanctions next week unless progress was made in ending a deadlock over how to implement a power-sharing deal.
Nobel laureate and South African Archbishop Desmond Tutu said on Thursday that Mugabe must step down or be removed by force and that he faced indictment for war crimes in The Hague unless he quit.
Rice said the stalled power-sharing talks, a "sham election" earlier this year, economic meltdown and the humanitarian toll from the cholera epidemic required swift action.
"If this is not evidence to the international community that it’s time to stand up for what is right I don’t know what will be," Rice told a news conference.
"Frankly the nations of the region have to lead it."
British Foreign Secretary David Miliband said in a statement that Zimbabwe’s neighbours should know there was "massive international support for any collective effort to bring a real change to Zimbabwe."
South Africa said on Friday that Zimbabwe’s call for international help was encouraging. "We think that that’s a major breakthrough," government spokesman Themba Maseko said.
Zimbabwe’s neighbours in the 15-nation Southern African Development Community have so far failed to persuade Mugabe and the opposition to form a unity government.
But, faced with Zimbabwe’s worsening economic collapse and the humanitarian crisis spilling over into their own countries, they may now be forced to take a stronger stand against the veteran Zimbabwean leader.
Zimbabwe, isolated by Western countries under Mugabe’s increasingly authoritarian rule, has the highest rate of inflation seen in modern times — officially 231 million percent, but prices are actually doubling every 24 hours.
Basic foods are scarce and the currency is worthless and often unavailable in banks.
Trade union activists took to the streets earlier this week to protest about the financial crisis, and dozens of protesters were arrested. Harare residents clashed with soldiers, accusing them of robbery.
"I think if we demonstrate and put pressure, things might change. We also need our leaders to understand that we are suffering, they should see to it that our demands are heard," said a Harare resident who identified himself as David.
The economic meltdown has left the health system ill-prepared to cope with the cholera epidemic that it would once have prevented or treated effectively.
The cholera outbreak follows the collapse of the water system, which has forced residents to drink from contaminated wells and streams. The disease has spread to neighbouring South Africa, Mozambique, Zambia and Botswana.
South Africa said it would send a team of senior government officials to Zimbabwe next week to assess the food crisis and investigate what aid is needed.
Thousands of Zimbabweans are believed to cross the border, often illegally, into South Africa each day. A cholera centre has been set up in the South African border town of Musina.
Mozambique said on Friday it had put all border areas on maximum alert over the threat of cholera, while Zambia said one Zimbabwean had died from the disease in a border town and two were receiving treatment.
Zimbabwe does not have the funds to pay doctors and nurses or buy medicine, and aid agency Oxfam said at least 300,000 people weakened by hunger are in danger from the epidemic.
South Africa will announce an aid package for Zimbabwe next week, Maseko said, adding that Zimbabwe’s political parties have agreed that all aid should be distributed in a non-partisan way.
Western nations, which accuse Mugabe of running the once prosperous nation into the ground, have also promised aid. EU ministers have agreed to provide an initial 200,000 euros ($254,000) to the Red Cross and other aid agencies