South African ruling party chief Jacob Zuma said Friday that the Southern African Development Community in summit on Sunday in Johannesburg must “force” parties to Zimbabwe's troubled power-sharing process to come to terms.

Zuma, president of the African National Congress and the country's presumptive next president following 2009 elections, told a Reuters reporter in Cape Town following a press event that the SADC summit “must make those Zimbabweans reach an agreement” because the crisis is spilling over into the Southern African region.

The summit is shaping up as a make-or-break event for the power-sharing process, particularly after the MDC formation led by prime minister-designate Morgan Tsvangirai accused the ZANU-PF party of President Robert Mugabe of putting a "full stop" to the process by relaunching political violence akin to that seen after March elections.

Foreign Minister Phandu Sekelemani, who will represent Botswana with Vice President Mompati Merafhe, told reporters that Khama was not snubbing the summit but had made the commitment to the bio-diversity conference months ago.

But the Botswana Guardian newspaper criticized Khama’s decision, saying he should have seized the opportunity to confront Mr. Mugabe.

Mr. Khama has been among Mr. Mugabe’s most outspoken critics. His recent suggestion that a new and internationally supervised presidential election would be in order if the power-sharing process failed brought a torrent of invective from Harare.

Political analyst Tom Serwetsi of the University of Botswana agreed Mr. Khama would be missing an opportunity – especially as he has never attended a SADC summit since assuming power in April from former president Festus Mogae.

Tsvangirai met today with Namibian President Hifukupunye Pohamba and was to meet Malawian president Bingu wa Mutharika in Malawi late Friday, by which time he would have met all but a few of the 15 SADC leaders ahead of the summit.

Tsvangirai's recent meeting with Khama sparked a row between Harare and Gaborone, with Zimbabwean government officials accusing Botswana of training MDC militants to bring down Mr. Mugabe's government.

Khama Press Secretary Jeff Ramsay told reporter Blessing Zulu of VOA's Studio 7 for Zimbabwe that the charge was unfounded and Harare must produce proof.

Spokesman Nelson Chamisa of the Tsvangirai MDC formation said the government is launching false allegations to justify clamping down on the opposition.

Pretoria-based Senior Analyst Sydney Masamvu of the International Crisis Group said Southern African leaders must direct their anger towards Mr. Mugabe.

More reports from VOA's Studio 7 for Zimbabwe...