Ivory poachers have killed more than 80 elephants in Zimbabwe by poisoning watering holes with cyanide, a minister said.
Members of Zimbabwe's opposition say they have been targeted by Mugabe supporters following the president's re-election.
President Robert Mugabe's declaration as winner has been met by international concern over the conduct of the African nation's poll.
President Robert Mugabe celebrated his 90th birthday today having spent more than a third of his life as leader of Zimbabwe.
Robert Mugabe celebrated his 90th birthday at a party-come-political rally in a football stadium, held a few days late due to a trip to Singapore for what aides said was a cataract operation.
Mugabe appeared to show no signs of ill health after returning from Singapore and his aides have denied speculation he has been treated for prostate cancer.
Zimbabwe's sole ruler since the former Rhodesia gained independence from Britain in 1980, Mugabe is under Western sanctions. He denies human rights abuses and election fraud and blames Britain for smearing his name.
Robert Mugabe turned 90 today, celebrating his birthday not in his native Zimbabwe, but in Singapore.
His spokesperson denied reports he was suffering from prostate cancer, saying it was a routine cataract operation.
In an interview on state television, Mugabe claimed to be as "fit as a fiddle" but his slightly slurred and slow speech, and languid appearance fuelled further speculation about his health.
The state broadcaster did manage to venture a question on who might succeed him within his party, but he denied there was any need to even discuss such a possiblity.
Former Prime Minister Tony Blair has denied claims his government asked South Africa for their support in invading Zimbabwe and toppling Robert Mugabe.
Thabo Mbeki, the former South African president, said his country and Britain had differing opinions on how to deal with Zimbabwe in 2000, when they were hit by an economic collapse and political repression. Mr Blair wanted Mugabe to go while Mr Mbeki favoured political negotiation.
Mr Mbeki, who served as president from 1999 until 2008, told Al Jazeera: "The problem was, we were speaking from different positions.
“There were other people saying ‘yes indeed there are political problems, economic problems, the best way to solve them is regime change. So Mugabe must go.’
"This was the difference. So they said ‘Mugabe must go’. But we said ‘Mugabe is part of the solution to this problem’.”
A spokesman for the former Prime Minister said: "Tony Blair has long believed that Zimbabwe would be much better off without Robert Mugabe and always argued for a tougher stance against him, but he never asked anyone to plan or take part in any such military intervention."
The number of poisoned dead Elephants at the Hwange National Park in Zimbabwe has risen to 91, wildlife officials have told the Associated Press.
The elephants were poisoned with cyanide by poachers who hacked off their tusks for the lucrative illegal ivory market. ITV News correspondent Martin Geissler reported on the devastating attack last week.
Officials say cyanide used in gold mining was spread by poachers over the flat "salt pans". They also say lions, hyenas and vultures have died from feeding on contaminated carcasses or drinking nearby.
Nine suspected poachers have been arrested this month after the biggest, most brutal poaching spree on record. Three men were sentenced to up to 16 years in jail.
Zimbabwe President Robert Mugabe has said that Britain and the US should not 'harass' the African nation, referring to sanctions that he says are pressuring his government.
"They should not continue to harass us, the British and Americans," Mugabe, Africa's oldest leader at 89, said at the funeral of an airforce officer.
"We have not done anything to their companies here, the British have several companies in this country, and we have not imposed any controls, any sanctions against them, but time will come when we will say well, tit for tat, you hit me I hit you."
Zimbabwe President Robert Mugabe threatened on Sunday to retaliate "tit for tat" against companies from Britain and the United States if these Western powers persisted in pressuring his government with sanctions and what he called "harassment".
Mugabe has fiercely rejected questioning from the West of a July 31 election that returned him to power in the southern African country he has ruled for 33 years. His main rival called the election a "huge fraud".
Zimbabwean President Robert Mugabe branded the West "vile" and said his critics could "go hang", shortly after taking his oath of office today.
"Except for a few Western dishonest countries, our elections have been hailed as peaceful, free, fair and credible," the 89-year-old told supporters in an hour-long speech.
– Zimbabwean President Robert Mugabe
For those odd Western countries who happen to hold a different negative view of our electoral process and outcome, there is not much that we can do about them. We dismiss them as the vile ones whose moral turpitude we must mourn.
A full National Sports Stadium in Harare watched Robert Mugabe sworn in as Zimbawe president for his seventh five-year term.