Chad's military government and dozens of opposition groups started peace talks on Sunday in Qatar as a first step towards ending a rebellion and holding elections. But after opening speeches, in which the country's prime minister and the head of the African Union Commission called for concessions, the talks were suspended for 48 hours because of a dispute over the format, opposition groups said.The landlocked African nation was thrown into turmoil by the killing of longtime leader Idriss Deby Itno in a battle with rebels last April.