Zimbabwe's opposition leader Morgan Tsvangirai has returned to Harare to begin his presidential run-off campaign, after spending weeks abroad. Police stood by as a convoy carrying the Movement for Democratic Change leader left the airport after touching down from neighbouring South Africa. Mr Tsvangirai's scheduled return last weekend was delayed amid allegations the army planned to assassinate him. The ruling party rejected the MDC claims as a fantasy. The presidential election run-off is scheduled to take place on 27 June despite warnings that election violence makes a fair second round impossible. Police assault Opposition and human rights groups have said hundreds of opposition supporters have been beaten up and at least 40 killed since the first round on 29 March. Mr Tsvangirai's first scheduled stop in Harare is at a private clinic to meet victims of political violence, says the BBC's Peter Biles in Johannesburg. Hospitals have been struggling to cope with admissions, our correspondent says, as a result of what is widely perceived to be a government campaign of intimidation against MDC supporters. President Robert Mugabe's ruling Zanu-PF party denies supporting violence and says the West is trying to demonise Zimbabwe. Last year, Mr Tsvangirai was treated in hospital after being assaulted by police. Mr Mugabe has accused the MDC of fomenting violence since the disputed first round election. Mr Tsvangirai has spent nearly two months outside Zimbabwe, mainly in South Africa, since the first round trying to drum up international support. According to official results, the MDC leader won the presidential poll, but not by enough to avoid a run-off with President Mugabe. The Zimbabwe Electoral Commission said Mr Tsvangirai won 47.9% of the vote, with Mr Mugabe taking 43.2%. Source: BBC