Zimbabwe's social welfare minister has told aid groups to stop field work in his country.
In a memorandum sent to aid groups late Thursday, the minister, Nicholas Goche, said he had learned that aid groups were violating the terms of their agreement with the government. He did not elaborate in the brief statement.
The statement says all aid and development groups are ordered to "suspend all field operations until further notice."
The pronouncement comes a day after opposition and rights groups criticized the violence and intimidation in the run-up to the presidential run-off, with some Zimbabweans worrying that President Robert Mugabe will try to steal the election.
On Thursday, a group of U.S. and British diplomats who were investigating reports of violence against the opposition were detained for several hours.
On Wednesday, Zimbabwean opposition leader Morgan Tsvangirai was detained in police custody for more than nine hours. Amnesty International condemned Tsvangirai's detention and said it was "part of a sudden, sharp and dangerous crackdown on political opposition in the run-up to the elections."
The organization also raised concerns about "severely tightening restrictions" placed by the government on international aid agencies distributing food and other assistance to Zimbabweans.
CARE International had been ordered to halt operations pending an investigation of allegations it was campaigning for the opposition. CARE denies that was the case.The organization provides aid to about 500,000 Zimbabweans.
Other aid groups have also been told to curb activities in Zimbabwe and there is concern the decision will worsen Zimbabwe's food security problems.
Zimbabweans increasingly are unable to afford food and other essentials with agriculture paralyzed by land reform and the world's highest rate of inflation.
"By introducing restrictions against aid workers in Zimbabwe, the Zimbabwean government is attempting to hide the worst of the state-sponsored violence from the eyes of the world," said Amnesty International.