Harare - The United Nations torture rapporteur Manfred Nowak refused entry to Zimbabwe said Thursday he believed President Robert Mugabe may be trying to cover-up a resurgence in political violence.

Nowak was addressing a press conference in Johannesburg after being turned back by immigration officials at Harare airport Wednesday night on the grounds that he didn't have "clearance" from the foreign ministry.

After spending the night at the airport, Nowak was forced to take the first plane back to Johannesburg on Thursday morning, despite having a letter of invitation from Prime Minister Morgan Tsvangirai and the agreement of the home affairs ministry.

Asked if he believed Mugabe had intervened directly Nowak said there were "strong indications that this was not just done by the ministry of foreign affairs without the knowledge or instruction of President Mugabe."

If Mugabe had intervened it would show that "the president feels it is not a good thing if an independent human rights expert assess the situation of torture and ill-treatment in the country," he said.

Nowak was initially invited to Zimbabwe by Justice Minister Patrick Chinamasa a member of Mugabe's Zanu-PF, to meet with prisoners, activists and officials and compile a report for the Human Rights Council in Geneva.

But on Monday, two days before the mission was due to begin, the foreign ministry revoked the invitation, saying that government would be too busy meeting with the Southern African Development Community and telling Nowak to postpone his visit.

The U-turn came amid a sudden worsening of relations between Mugabe's and Tsvangirai's parties that threatens the future of the country's eight-month-old unity government.

Three southern African ministers met with Mugabe and Tsvangirai Thursday for talks on how to steer the government out of a crisis triggered by an MDC boycott of cabinet. The MDC said two weeks ago it was "disengaging" from Zanu-PF until the party stopped thwarting the implementation of key reforms.

Nowak, who was already in Johannesburg when he received the order to postpone his visit, said he pressed ahead after Tsvangirai confirmed a meeting for Thursday, although he knew he might be rebuffed.

The fact that Tsvangirai's wishes had been ignored "sheds a real light on where the real power in this unity government is lying," and was a "very, very alarming signal in relation to the working or non-working of the unity government," he said.

The Austrian expert, who was named special rapporteur in 2004, said he would be reporting back to the Human Rights Council that the mission had failed.

Even if the government apologized and he was invited back, "there will be no other mission, at least as long as I am UN rapporteur on torture," because there was no mutual trust, he said.

At the same time he "deeply regretted" not having a chance to investigate "the rumours, allegations and partly facts about the deteriorating human rights situation in the country."

"There are definitely indications about a rise in violence, harrassement and intimidation" since the MDC cabinet boycott began, he said, backing similar claims by the MDC.

Both Nowak, Amnesty International and the MDC have warned of a return to the violence that characterized last year's presidential election run-off.

Nowak said he had credible accounts of a new wave of violence in rural areas. In Harare an MDC residence was ransacked by police allegedly looking for weapons at the weekend and a MDC official was since allegedly abducted by state agents. (dpa)