Two army officers have been arrested in Burundi in connection with the killing last month of 173 people in Gitega Province.

President Pierre Buyoya said the officers - the second-in-command of a battalion and a junior officer - had been operating in the area at the time of the killings.

"They are in the hands of the law," he told journalists.

The Burundian army had earlier admitted that its soldiers were responsible for last month's killings, but tried to transfer responsibility to Hutu rebels; it said the army had warned civilians to leave because an attack was imminent, but the rebels had told them to stay put.

Burundi conflict

War began: 1993 200,000 killed Hutus: 85% Tutsis:14% Twa: 1% Tutsis have dominated since independence

Two weeks ago, the Burundian Government announced an investigation saying there had been "errors of judgement".

At the time, the chairman of the parliament's human rights committee, Leonidas Ntibayazi, said the armed men who carried out the massacre had ordered people out of their houses and "then told them to lie down and shot them in cold blood".

The killings took place in a region which has seen fierce fighting between Hutu rebels and the Tutsi-dominated army.

Heavy fighting between government troops and rebels of the Forces for the Defence of Democracy (FDD) has been going on for several months as South African mediators attempt to get the several rebel groups involved in Burundi's nine year civil war to agree to a cease-fire.

At least 200,000 people, most of them civilians, have been killed, but many deaths go unreported.