"We had to tell Mbeki it was no use continuing with negotiations with someone who does not want to negotiate."
Mugabe on Friday declined to explain the deadlock in the talks, saying only: "They went well in the wrong direction."
The Southern African Development Commission's three-nation security panel, made up of the heads of state of Swaziland, Mozambique and Angola, is due to meet on Monday to discuss how the deadlock can be broken.
"We call upon the Sadc and the AU [African Union] to use their collective wisdom to help unlock the deadlock," Tsvangirai said.
"It was one-man monologue. Mugabe does not negotiate. He just says 'No'"
Zimbabwe prime minister-designate
"Hopefully there will be a breakthrough next week."
The two men signed a deal one month ago which calls for 84-year-old Mugabe to remain as president while Tsvangirai would take the new post of prime minister, with cabinet posts being shared out by the rivals' two parties and a breakaway faction of the MDC.
But last week Tsvangirai threatened to pull out of the deal after Mugabe unilaterally awarded the most important ministries to his party, leaving him in charge of the military and police.
Patrick Chinamasa, lead negotiator for Mugabe's Zanu-PF party, said in the state media that the talks hinge on control of the home affairs ministry which oversees the police force.
He told the Herald newspaper that Zanu-PF had agreed to give the MDC control of the finance ministry, a critical post in a country grappling with the world's highest rate of inflation.
"One can say that the discussions, however, largely centred on the issue of home affairs. Zanu-PF was arguing that it should get the ministry while [Tsvangirai] was also arguing that they should get the ministry," Chinamasa said.
Lovemore Madhuku, chairman of the National Constitutional Commission, told the AFP news agency that it was likely that Sadc would push Mugabe to hand over control of home affairs to the MDC.
"Eventually they will come to an agreement. Both parties are desperate to remain in the deal," he said.
No 'plan B'
Briggs Bomba, an analyst from Africa Action, said neither Zanu-PF nor the opposition had a clear advantage in the power-sharing talks.
"The opposition does not have a clear 'plan B' on how it can dislodge Mugabe from power besides talking to him and sharing power," he told Al Jazeera.
"Zanu-PF, on the other hand, does not have a solution to the economic crisis which does not involve bringing in the opposition and repairing relations internationally.
"We are maybe going to have a completely different mediator and an increased role by the African Union and Sadc," he said.