Images of a badly beaten Tsvangirai and his supporters have triggered condemnation, particularly from Mugabe's opponents in London and Washington, but Mugabe showed no signs of softening his stance.
At a joint press conference with Kikwete, Mugabe said: "When they criticise the government when it tries to prevent violence and punish perpetrators of that violence we take the position that they can go hang.
"Here are groups of people [the MDC] who went out of their way to effect acts of violence.
"We hear no criticism to this campaign from Western governments. This is the West that has always supported the opposition elsewhere, again showing its true colours. We don't accept their criticism."
A foreign ministry official in Tanzania had said that Kikwete had gone to mediate between Mugabe's Zanu-PF party and the MDC, citing the worldwide condemnation that was triggered by the apparent assaults on the opposition.
But the Tanzanian president, who has recently returned from Europe, gave few details about the talks with Mugabe.
"I came to brief the president on my visit to Europe and discussions that always come up on the situation in Zimbabwe," he said.
"There are so many issues we discussed and we agreed on the way forward on a number of issues."
Tanzania, along with Namibia and Lesotho, is charged with dealing with the Zimbabwe crisis within the Southern African Development Community (SADC), a 14-nation regional bloc promoting development and democracy in the region.