South Africa's governing ANC party has accused the Zimbabwean government of "riding roughshod" over democracy. The party said it was "dismayed" by the authorities' actions, and that free and fair elections were not possible. A BBC correspondent says this is the strongest statement so far by the ANC on Zimbabwe and a sign of mounting diplomatic pressure on its government. Zimbabwe's opposition MDC has formally withdrawn from Friday's presidential run-off election. Morgan Tsvangirai, leader of the Movement for Democratic Change (MDC), announced he was pulling out of the race at the weekend, citing widespread violence as the reason. On Tuesday the MDC said it had hand-delivered a letter to the country's electoral commission confirming it would not participate in the run-off. 'Compelling evidence' The ANC said it was "deeply dismayed by the actions of the Zimbabwean government - which is riding roughshod over hard-won democratic rights". It said it could not remain "indifferent to the flagrant violation of every principle of democratic governance". And the party referred to "compelling evidence of violence, intimidation and outright terror". The comments come a day after the UN Security Council unanimously agreed to condemn the violence in Zimbabwe and said a fair election would be "impossible". The BBC's Peter Biles in Johannesburg says that coming from South Africa - the most powerful country in the region - the statement is a further sign of President Robert Mugabe's growing isolation. South African President Thabo Mbeki has been adopting a policy of "soft diplomacy" towards Zimbabwe. In separate comments, ANC leader Jacob Zuma, who rivals Mr Mbeki as South Africa's most powerful man, said the situation in Zimbabwe was "out of control" and called for urgent intervention by the UN and regional Sadc grouping. Meanwhile, Mr Tsvangirai said he would leave the Dutch embassy in Harare sometime over the next 48 hours. 'Cry baby' Mr Tsvangirai, who took refuge there on Sunday night hours after pulling out of this Friday's vote, said the Dutch ambassador had received assurances from the Zimbabwean authorities about his safety. Senegalese President Abdoulaye Wade, in a statement about his attempts to mediate in the Zimbabwe, said Mr Tsvangirai had been fleeing soldiers when he took refuge at the embassy in Harare. BBC world affairs editor John Simpson, who is in Harare, says few people in Zimbabwe know Mr Tsvangirai has pulled out of the race as official media barely ever mention him. Meanwhile, Zimbabwe's UN ambassador Boniface Chidyausiku told the BBC Mr Tsvangirai, who was briefly detained five times while campaigning, had never had his movements restricted by the authorities. "He's a cry baby... He has been free to move wherever he wanted to move," he said. In other developments on Tuesday: • Robert Mugabe, quoted by the pro-government Herald newspaper, accused Western countries of "telling a lot of lies about Zimbabwe" in order to justify an intervention • Former UN High Representative in Bosnia and Herzegovina Paddy Ashdown, a British politician, warned Zimbabwe's violence could descend into genocide like that in Rwanda in 1994 • An African election observer, who does not want to be named, told the BBC torture was "the order of the day" in Zimbabwe The opposition says some 86 supporters have been killed and 200,000 forced from their homes by Zanu-PF militias but the ruling party blames the MDC for the violence. Meanwhile, the BBC's Themba Nkosi in Bulawayo, south west of Harare, is reporting that youths and villagers from an MDC faction have this week been ambushing and attacking pro-Zanu-PF so-called war veterans in the area. The MDC won the parliamentary vote in March, and claims to have won the first round of the presidential contest outright. According to official results, Mr Tsvangirai was ahead of Mr Mugabe but failed to gain enough votes to avoid a run-off. Source: BBC