The United Nations, the European Union, Britain and aid agencies expressed grave concern Friday at the plight of millions of needy Zimbabweans affected by a ban imposed on nongovernmental organizations carrying out field work, according to dpa. Aid agencies and NGOs were meeting Friday to discuss the bombshell letter from Public Service Minister Nicholas Goche Thursday, ordering them to suspend their field activities, because some had "breached the terms and conditions of their registration." The agencies said the ban would wreak "untold harm" on the country, where around 4 million people, a third of the population, relies on food aid and The United Nations said its humanitarian work in Zimbabwe was under threat if it could not rely on the help of the NGOs. "The consequences would be very dramatic," said Elisabeth Byrs of the Office for the Coordination of Humanitarian Affairs (OCHA) in Geneva. "If we haven't these NGOs with whom the UN works then the humanitarian programme can't be carried out and it's the population that suffers," said Byrs. The European Commission, the biggest donor of aid to Zimbabwe, demanded that the ban be lifted immediately, while Britain, Zimbabwe's former colonial power, accused President Robert Mugabe of using hunger "as a political weapon." "I am deeply distressed to think that hundreds of thousands of people who depend on aid from the European Commission and others for their very survival now face an even more uncertain future," said Louis Michel, the EU executive's commissioner in charge of development and humanitarian aid. "For Robert Mugabe to use the threat of hunger as a political weapon shows a callous contempt for human life," Douglas Alexander, Britain's International Development Secretary, said. A spokesman for Prime Minister Gordon Brown described the situation in a country that was once a net exporter of food a "tragedy." In Geneva, the High Commissioner for Human Rights Louise Arbour also condemned the measures. "This is an unconscionable act. To deprive people of food because of an election would be an extraordinary perversion of democracy and a serious breach of human rights law," she said. But Mugabe's government, which has accused some NGOs of openly campaigning for the opposition Movement for Democratic Change (MDC) in March elections, shrugged off the criticism. "I think people should leave Zimbabwe to manage its own affairs," Deputy Information Minister Bright Matonga told the BBC. Matonga was also reported as saying that all the NGOs would have to reapply for accreditation but an employee with a British-based aid agency told Deutsche Presse-Agentur dpa in Johannesburg they had yet to receive any such instructions. The ban, coming three weeks ahead of a run-off presidential election between Mugabe and MDC leader Tsvangirai, has sparked suspicion the state wants to close off troubled rural areas to outside observers. Some NGOs had already complained that their distribution of aid in rural areas worst had been been severely hampered by a campaign of militia violence targeting mainly opposition supporters in the wake of the March elections. Zimbabwe, once the breadbasket of southern Africa, now suffers perennial food shortages prompted by a disastrous land reform campaign, recurring drought and a shortage of foreign currency for farm inputs. This year's wheat yield is already expected to be risible with state media reporting 53 per cent less wheat planted compared to last year. The government last week already began moving against the NGOs, ordering British-based charity Care International to suspend its aid efforts, which reach 500,000 people, because of its "political activity" - a charge Care has vehemently denied. Care's Africa communications director Kenneth Walker described the situation as "very serious" while Judith Melby of the Christian Aid charity, told the BBC the decision was "quite frightening, frankly." Thursday's blanket directive came after the close of a UN summit on hunger in Rome, where Mugabe had accused the West of being responsible for his country's hardships. Zimbabwe's children and 1.6 million HIV patients are deemed particularly vulnerable to the state's decision. The life-prolonging antiretroviral drugs used by HIV patients are only effective if taken with food. A representative for the UN children's agency UNICEF in Zimbabwe said hundreds of thousands of children were also in need of "immediate assistance."