Going through the numerous security checks in place, the journalist was asked to put his bag down for a sniffer dog and when asked if he had anything in his bag, he quipped, "No, just an explosive notebook".

Police then went into talks with presidency officials and US embassy officials, and it was decided the man should be taken away. As he walked away from the reporter, the embassy official said "bad joke".

U.S. Secretary of State Hillary Clinton will push South Africa to use its influence with neighbour Zimbabwe, while also seeking closer ties with Pretoria after strained relations with the Bush administration.

Clinton, set to meet South Africa’s foreign minister and vice president on Friday, said she would urge the new government to get Zimbabwe to raise the pace of political reform which has been too slow for donors to release substantial amounts of aid.

South Africa must, she said, "try to use its influence to mitigate against the negative effects of the continuing presidency of President (Robert) Mugabe."

New South African President Jacob Zuma, due to meet Clinton in the coastal city of Durban on Saturday, has taken a harder line on Zimbabwe than his predecessor Thabo Mbeki, but the United States wants more.

The United States, troubled by what it sees as an absence of reform in Zimbabwe, has no plans either to offer major aid or to lift sanctions against Mugabe and some of his supporters.

Before any of that can happen, Washington wants more evidence of political, social and economic reforms by Mugabe and the government he shares uneasily with opposition leader and now Prime Minister Morgan Tsvangirai.

Mugabe, in power since independence from Britain in 1980, is blamed for plunging Zimbabwe into economic ruin. He argues that his country’s economic woes, which include hyperinflation and a collapsed infrastructure, are caused by sanctions.

GOODWILL 

Clinton hopes there will be a burst of goodwill due to the change of government in both South Africa and the United States and that she will be able to kick off better relations with Pretoria that the Bush administration had.

"Under Thabo Mbeki, U.S.-South African relations were not as warm and friendly in reality as many people thought," said a senior official, who spoke on condition he not be named.

The United States had disagreed, for example, with Mbeki’s views on how to handle the HIV/AIDS crisis, which the former South African president had been slow to grasp.

Walter Kansteiner, a top Africa diplomat for the Bush administration, said Clinton should work Zuma "very hard" on Zimbabwe and follow up with him after their meetings.

"I think we left Pretoria off the hook too many times on Zimbabwe … but in our defence there were a lot of other issues on our agenda and the feeling was why jeopardise all these many other things that we were trying to get done," he said.

While in Nairobi — the first stop of Clinton’s seven-nation African tour before she came to South Africa — the top U.S. diplomat publicly lambasted Kenya’s government for corruption and poor governance.

U.S. officials said Clinton would not beat the same drum with Pretoria and the focus would be on boosting economic and diplomatic ties.

"The South African government does not have the serious issues of corruption that plagued the Kenyan government," said the U.S. official.

Clinton visited South Africa several times when her husband, Bill Clinton, was U.S. President and she plans to visit Cape Town on Saturday to check in on progress at a housing project named after slain anti-apartheid activist Victoria Mxenge, which she went to saw on two previous trips.

On Friday she will also meet international icon and former South African president Nelson Mandela.