Zimbabwean President Robert Mugabe and two other major contenders for his job filed papers on Friday to make their candidacies official, setting the stage for a race to the finish just a little over six weeks away when elections are held on March 29.

Seeking to unseat Mr. Mugabe, who is to turn 84 on Feb. 21, are Morgan Tsvangirai, founder of the opposition Movement for Democratic Change, and Simba Makoni, until very recently a senior member of Mr. Mugabe's ruling ZANU-PF party.

A fourth candidate, independent Langton Toungana, is virtually unknown.

little known and politician s uspected to have been fielded by the establishment to help split the opposition v ote, and validate the poll after earlier opposition threats to boycott the elect i on over demands for electoral reforms and new constitution.

Even as the three candidates filed papers or had them filed on their behalf in Harare, the contest took on a new dimension as Arthur Mutambara, leader of an MDC faction in rivalry with Tsvangirai's own formation, threw his support behind Makoni.

Mutambara urged others in the opposition to join a united front against Mr. Mugabe.

Correspondent Irwin Chifera of VOA's Studio 7 for Zimbabwe reported from the news conference at which Mutambara publicly set aside his own presidential ambitions.

The Makoni-Mutambara alliance poses a threat not only to Mr. Mugabe, but also to Tsvangirai, who in his own news conference this week praised Makoni's "courage" in breaking with Mr. Mugabe and the ruling party, but called him a latecomer who had to answer to voters for staying with ZANU-PF through years of national decline.

Researcher Chris Maroleng of South Africa?s Institute for Security Studies told reporter Patience Rusere that while Mutambara?s grouping is considered the lesser grouping in the MDC, its popularity in western Matebeleland is a plus for Makoni, who like Mutambara and Tsvangirai has his origins in eastern Manicaland Province.

Nomination papers for the three main presidential candidates were filed in the high court premises in Harare's Mashonganyika Building, while those for candidates for the house and senate were filed in magistrates court on so-called Rotten Row.

Correspondent Thomas Chiripasi reported on the day's proceedings.

In Bulawayo, Zimbabwe's second-largest city, hopeful candidates spent Friday milling around in the Tredgold Court Building waiting to file nomination papers.

Sources said Zimbabwe Electoral Commission staff took two hours to process each application, as correspondent Netsai Mlilo reported.

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