The MDC and other rights groups say Tsvangirai and 49 other opposition figures who were detained for three days were tortured after attempting to attend a banned rally.
Tsvangirai's arrest and alleged torture has provoked international condemnation and has brought attention to Mugabe's controversial rule as Zimbabwe suffers its worst economic crisis in decades.
"It is a course of ruin, both electorally and in terms of their future as a lawful opposition"
Sikhanyiso Ndlovu, Zimbabwe information minister
Al Jazeera, the only international network with a permanent presence in Zimbabwe, spoke exclusively to Morgan Tsvangirai in a Harare hospital, who said he had suffered "a traumatic experience".
Tsvangirai said that he had received injuries to his "head, back, hands, broken bones, and the knees they are severely bruised."
"I don't know how long I'll be inside [the hospital]," he said.
In a statement on Wednesday, Mugabe's government suggested that Tsvangirai and his MDC colleagues had been assaulted for resisting arrest and for launching a violent drive to overthrow his ZANU-PF party.
"The Tsvangirai faction of the MDC has a long record of unleashing violence to achieve political goals. It has publicly restated its wish to use violence to overthrow government and as a means to power," Ndlovu said.
"This will come to grief," he added.
The Zimbabwe government said that a number of Western governments, including the UK and US, had made "unconditional statements of support to the violent MDC" while international media networks absolved the opposition of blame.
The government said the MDC's drift towards "violent confrontation and blatant thuggery" had seen it lately organising illegal meetings and protests, inciting anti-government violence in townships.
The government also accuses the MDC of encouraging criminal attacks on police officers, arson and looting of shops.
"In particular, government has noted the MDC leadership's publicly announced mission to seek to topple the government through civil unrest in order to realise the British-led goal of 'regime change' in Zimbabwe," the statement said.
Mugabe's government said the MDC, which accuses the ruling party of rigging its way to victory in three major elections since 2000, was pursuing a violent path because it had no popular support.
"It is a course of ruin, both electorally and in terms of their future as a lawful opposition," Ndlovu said.