HARARE, Zimbabwe — Sitting in the shade of a tree in his well-tended garden, and cared for by his wife Susan, the battered Zimbabwean opposition leader nursed his swollen face.

With his arm still in a splint since a savage beating in police detention 10 days ago, Morgan Tsvangirai talked to the Daily Telegraph and gave a bleak assessment of the chances of a peaceful transition to democracy in his country.

Mr. Tsvangirai said President Mugabe’s strong-arm tactics to crush all rivals to his dictatorial rule had “entered a new phase” that signaled “the beginning of the end” for Mr. Mugabe’s regime.

The founder of the Movement for Democratic Change and some of his closest allies have been the victims of state-sponsored violence.

Mr. Tsvangirai alleged that a new undercover security force had been deployed by Mr. Mugabe and his security minister, Didymus Mutasa, to mete out intimidation and brutal attacks.

“Instead of random beatings at police stations, [Mr. Mugabe] is now using hit squads, unidentified men, unidentified vehicles,” he said.

“But we know these are units of state agents that have been given this assignment.”

The vocal and energetic MDC party spokesman, Nelson Chamisa, was left with a fractured skull when he was attacked by eight men, one armed with an iron bar, as he checked in for a flight to Brussels at Harare’s international airport on Sunday. His assailants wore military-style clothing and fled in cars with no registration plates.

Mr. Tsvangirai said police officers “disagree with me, but not so violently that they wish me to die,” and that it was special units of young militants, hand-picked for their loyalty to the Mugabe regime, who were carrying out the violence under orders from the top.

“I can assess who is in charge of this — it is coming directly from Mugabe. Mugabe is a violent man and he doesn’t hide it, especially where his power is threatened,” Mr. Tsvangirai said.

“No excuses, no regrets — the defiance epitomizes his attitude.”

Mr. Mutasa, who is one of Mr. Mugabe’s closest aides, yesterday denied Mr. Tsvangirai’s claims. “It is a flat lie,” he said. “He and his group are the people who started the whole process in defiance of the government’s order not to hold a rally at a specific place,” he said.

On the morning before his beating, Mr. Tsvangirai said his wife had “jokingly” warned him that he would be arrested as he left their comfortable Harare home for the rally at which he was detained.

The U.S. State Department said yesterday that it held Mr. Mugabe “personally responsible” for the attacks on Mr. Tsvangirai and his colleagues.

The swell of international condemnation, including a rare rebuke to Mr. Mugabe from the African Union, has put Zimbabwe at a “tipping point,” Mr. Tsvangirai said.

He added: “If I were [a member of the ruling party] Zanu-PF, I would start saying this is the end or … the beginning of the end. I suspect any dictatorship raises the threshold, and I think this is a new phase.”

But he said the new strategy might be backfiring on Zimbabwe’s increasingly isolated leader as it has widened splits in his own party.

It is thought by some observers that if robust criticism is repeatedly directed at the regime, senior members may ultimately wish to distance themselves from the 83-year-old leader, precipitating the collapse of his rule.

“We can’t deteriorate to this level of international isolation — international condemnation at this level, when not even our friends will support us any longer, not even our sympathizers will justify this level of barbarity,” Mr. Tsvangirai said.

“So a lot of them are having very serious self-reflection about their future.”

Mr. Chamisa was on his way to a meeting of African, Caribbean, and Pacific MPs being held by the European Union in Brussels when he suffered serious injuries as he was attacked at the airport.

But yesterday, Zanu-PF delegates faced no obstacles to attending the conference, which begins today, despite E.U. sanctions against Harare.

Despite calls for action to prevent regime figures from traveling to Brussels, the Foreign Office said claimed that its hands were tied.

“E.U.-African, Caribbean, and Pacific meetings are covered by exemptions to the visa ban, so any member state would be obliged to issue a visa,” a British official said.

The approach has angered the shadow foreign secretary, William Hague, who called for action against Zimbabwe yesterday.

“Now is the time when Britain should be urging the international community to impose additional penalties on the regime in Zimbabwe,” he said.