• The opposition Movement for Democratic Change's (MDC) second in command, Tendai Biti, has appeared in court in the Zimbabwean capital, Harare, following his arrest last week on charges of treason
• An election observer has been killed in an attack in Karuru, a town north of Harare, early on Tuesday, as his family looked on, a local observer group said.
• The government has lifted a ban on aid agencies which distribute food and Aids treatment
• Local election observers are to be screened by the government to ensure they have "no preconceived ideas" about the vote
• A United Nations human rights official sent to Zimbabwe has been expelled
• UN envoy Haile Menkerios met Mr Mugabe on Tuesday and is expected to meet other politicians during a five-day visit, but state media is playing down his role
Mr Biti appeared in court in leg irons, amid heavy police presence. Mr Biti, who looked tense, was denied access to his lawyers.
Court proceedings have been adjourned until Thursday as there was no electricity in the courtroom.
Mr Khumalo, head of the Pan-African Parliamentary observers, said it was the government's responsibility to stop the violence which erupted after the first round of the elections.
Observers' chairman Marwick Khumalo on the violence in Zimbabwe
"It's very difficult to me to judge the degree of the violence in terms of whether it's decreased or it has escalated," Mr Khumalo told the BBC's Network Africa programme.
"But what is disturbing is that in a situation such as an election atmosphere... violence is one thing that you don't want to see happening, because it has the capacity of spoiling an election."
Western observers have been banned from the election.
The house of recently elected opposition Harare Mayor Emmanuel Chiroto was burnt down in an attack on Monday night.
"The maid escaped out the back and heard two bangs. I think it was petrol bombs. The house went up in flames and they took my wife and son. My wife was screaming," Mr Chiroto told the UK's Daily Telegraph newspaper.
There has been growing international concern about the political violence
He said that his son was later dropped off at a police station but his wife has not been seen since.
A neighbour said that mourners had gathered at the house on Wednesday morning, but they were dispersed by police.
There has been growing international concern that political violence will make a free and fair vote impossible.
South Africa's President Thabo Mbeki, who had been leading regional mediation efforts to resolve the crisis in Zimbabwe, is to meet Mr Mugabe in Bulawayo on Wednesday.
Meanwhile, Kenyan Prime Minister Raila Odinga called on President Mugabe to step down from office, saying the vote had already been rigged and Zimbabwe was "an eyesore".
Mr Tsvangirai's MDC says it is now being forced to run its election campaign in conditions of virtual secrecy.
The reality here is that that violence is by MDC against Zanu-PF members and the targets are war veterans
The MDC says at least 66 of its supporters have been killed and some 25,000 driven from their homes.
But Justice Minister Patrick Chinamasa blamed the clashes on the MDC.
"The reality here is that that violence is by MDC against Zanu-PF members and the targets are war veterans and, also, supporters of Zanu-PF who are in Zanu-PF's political strongholds," Mr Chinamasa told the BBC.
"A lot of the violence is committed by thugs who are bussed from urban areas, such as Harare, and they go during the night to target our people, to burn their houses."
There is uncertainty about Haile Menkerios' role
Meanwhile, Mr Chinamasa said that election observers were to be assessed "in respect to their independence and neutrality," Zimbabwe's state-run Herald paper reports.
Two leading UN agencies, the World Food Programme and the Food and Agricultural Organization, have warned in a new report that more than five million people in Zimbabwe are at risk of going hungry by the start of next year.
Falling grain production, lack of seeds and fertiliser, and rising fuel costs will cause hardship and food insecurity among both rural and urban populations in Zimbabwe, they say.
The Herald also reported that aid agencies which run supplementary feeding schemes and Aids treatment projects will not be subject to a ban imposed earlier this month after President Mugabe accused them of siding with the opposition.
UN High Commissioner for Human Rights Louise Arbour did not name the official who had been expelled or the reason why.
"Unfortunately it seems to fit in a pattern of the government taking a very unco-operative attitude" towards aid workers, she said.
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