By Alain Iloniaina
ANTANANARIVO (Reuters) - Madagascar's government has replaced a third of the country's regional governors with senior military officers, raising concern that a run-off vote in the first presidential election since a coup in 2009 will be rigged.
European and southern African observers said polling in the first round had been free and fair. But diplomats have warned the electoral process could still be derailed.
December's ballot pits against each other two aspirants backed by Madagascar's biggest political rivals - coup leader Andry Rajoelina and the man he ousted, Marc Ravalomanana.
"We are worried by this decision which comes on the eve of the second round," Mamy Rakotoarivelo, president of the national assembly and a senior figure in the Ravalomanana camp, told Reuters.
"We're worried that pressure, direct or indirect, will be put on voters."
A government statement issued on Wednesday showed changes to 10 of the Indian Ocean island's 22 regions. Three generals and five colonels assumed control of eight regions while two civilians head the remaining two.
The government said the step was taken because of "the candidacies of some regional leaders in legislative elections, recent insecurity and the national political context."
Most of the regions where new military leaders have been appointed are on the coast, where populations tend to be denser than the vast interior of the world's fourth largest island.
"Rajoelina is trying to gain control of coastal areas in the second round," said Lydie Boka of French risk group StrategiCo.
"His guy lost miserably in Antananarivo and wants to make sure his guy wins in the coastal regions," she said, adding that it was in these regions Rajoelina's candidate could counter Robinson's domination in the capital.
Prime Minister Omer Beriziky told reporters that while regional appointments were normally political, "neutral personalities" were needed this close to the election.
The army's neutrality is questioned, however. The army chief now was a middle-ranking officer who led the dissident troops that swung behind Rajoelina's street protests calling for the departure of Ravalomanana in early 2009.
Parts of the military's top command oppose Ravalomanana's return from exile, diplomats and supporters of the former president say.
On Wednesday, the island's electoral court confirmed Hery Rajaonarimampianina, a former finance minister and political ally of Rajoelina, and Jean Louis Robinson, once a minister under Ravalomanana, would contest the second round.
Both candidates fell far short of the 50 percent needed for an outright win.
(Additional reporting and writing by Richard Lough in Nairobi; Editing by Drazen Jorgic and Angus MacSwan)