Maseru - Southern Africa's regional body on Wednesday said it was sending a rapid-response team to probe the assassination of Lesotho's army commander, a killing it lashed as "barbaric" and a blow to peace efforts.The Southern African Development Community (SADC) has been trying to foster peace in Lesotho, but the death threatens to revive unrest in the mountain kingdom.Army commander Khoantle Motsomotso was shot dead at a barracks on Tuesday when two senior officers - widely seen as from a rival faction - tried to force their way into his office.The two officers were killed by Motsomotso's bodyguards.The bloody shootout took place just two months after elections meant to usher in a new era of stability."SADC strongly condemns this indescribable and inexcusable barbaric and heinous act," the group said in a statement.Peace and stability "This development is a serious blight and setback to the ongoing efforts to restore peace, security and stability to the Kingdom of Lesotho."The SADC team, due to arrive in Lesotho on Thursday, will work to "establish the root causes of the assassination and subsequently recommend the appropriate courses of action".On Wednesday, the leader of opposition in parliament, Mathibeli Mokhothu, said he doubted whether the SADC could calm the country's violent political climate."SADC decisions are far from assuring peace and stability in Lesotho, instead they are only fuelling divisions," Mokhothu told AFP.The two officers killed in the shootout - Tefo Hashatsi and Bulane Sechele - were among soldiers that the SADC has said should be prosecuted for the murder of former army commander Maaparankoe Mahao in 2015.Serious security issues Prime Minister Thomas Thabane's new coalition took office in June after the third general election since 2012, as Lesotho endures a series of political upheavals.Thabane, 78, previously served as premier after the 2012 elections.But he was forced to flee to South Africa - which entirely surrounds landlocked Lesotho - following an attempted coup two years later."SADC chose to address political problems but not the serious security issues," political analyst Kopano Makoa, of the National University of Lesotho, told AFP."Facilitating elections while leaving security issues behind shows that SADC missed the point."Critics accuse the military of favouring Thabane's old rival, Pakalitha Mosisili, who ruled from 1998-2012 and 2015-2017.