International aid agencies say Zimbabwe's government has ordered some groups to suspend their work because of alleged political activity.

A spokesman for U.S.-based CARE International told VOA Tuesday the government has accused its staff of distributing brochures for the opposition Movement for Democratic Change.

CARE's Africa communications manager, Kenneth Walker, denied the accusation.  He said the agency has strict policies against political involvement. 

Walker confirmed that CARE has suspended operations in Zimbabwe, saying the ban will affect about half a million people.

Another U.S.-based agency, World Vision, said the government has accused humanitarian groups of using food aid to campaign for the opposition.

World Vision said it is continuing minimal operations in Zimbabwe, despite what it called a crackdown on non-governmental organizations.

Zimbabwe is preparing for a June 27 run-off election between President Robert Mugabe and opposition leader Morgan Tsvangirai.

Morgan Tsvangirai delivers a speech in Harare, 30 May 2008

Mr. Tsvangirai told VOA Zimbabwe project that the army has seized control of large parts of the country and is blocking the opposition from campaigning there.  He said he was forced to call off a campaign rally in Matebelaland South Province because police said his security could not be assured.

Human rights groups and MDC officials have accused Mr. Mugabe's supporters of killing and brutalizing opposition activists in the run-up to the voting.  The president denies the charges and accuses the MDC of carrying out its own attacks.

In the capital, Harare, today, a court granted bail to the leader of an MDC faction who was arrested Sunday for publishing an article critical of President Mugabe.

After his release, Arthur Mutambara accused the president of violating people's human rights.  He is to appear in court on June 17.

Mutambara split from the main MDC party in 2005, but has agreed to join forces with Mr. Tsvangirai to try to unseat President Mugabe in the run-off election.