Article published on the 2009-01-30 Latest update 2009-01-30 16:02 TU
"We are unequivocal, we will go into this government," Tsvangirai told journalists after a meeting of the MDC's National Council.
But he also told supporters that all party members detained by security forces must be released before 11 February and said that "outstanding issues", such as the sharing out of cabinet posts and provincial governorships, will be submitted to the SADC before then.
The SADC plan, which Zanu-PF has already accepted, called for Tsvangirai to be given the top government job by that date.
Government ministers welcomed the MDC decision, claiming it is as a break with policies dictated by foreign powers.
"We are happy that for the first time they have now recognised themselves as Zimbabweans and we are happy that they are shifting from external influence and have started to reason like Zimbabweans," Information Minister Paul Mangwanatold the AFP news agency.
As the World Health Organisation declared that 3,161 have died in the cholera epidemic which is sweepiong the country and that 60,000 people are now infected, analyst John Makobe says that was among the considerations which influenced the MDC.
"The humanitarian problems that are being faced by the people of Zimbabwe were a very significant factor in the MDC deciding this time to join," he told RFI. "Otherwise the suffering of the people is too much."
"They are hoping that, once they are in, they can occupy space that Zanu-PF is not able to occupy … and slowly they will be able to reduce the space that Zanu-PF currently holds."