JUBA - Government troops in South Sudan were advancing Monday on Bor, the last state capital still in rebel hands, as peace talks in neighbouring Ethiopia appeared to make little progress towards a ceasefire.“Bor is still in the hands of the rebels but our forces are still moving towards it,” Colonel Philip Aguer said. Bor, the capital of the restive Jonglei State some 200 kilometres (125 miles) north of Juba, has already changed hands three times since fighting broke out in South Sudan one month ago.The fighting is between forces loyal to President Salva Kiir and a loose coalition of army defectors and ethnic militia nominally headed by Riek Machar, a former vice president and seasoned guerrilla fighter. Negotiators for both sides met for the first time in five days in the Ethiopian capital Addis Ababa in the hope of reaching a ceasefire agreement.Mediators from the East African regional bloc IGAD are trying to bring the two sides to a compromise over the issue of 11 pro-Machar figures who were arrested by loyalist forces shortly after the fighting erupted on December 15.Machar’s side has insisted the detainees should be released, while Kiir is equally adamant they should face justice. “We continue to put pressure on both sides - on both sides to sign the agreement and also on the government to agree to the release of the 11 ... who remain detained in Juba,” US envoy Donald Booth told journalists Sunday. Government troops recaptured the key north oil city of Bentiu last week, but have since grappled with rebel fighters closer to the capital Juba - with new clashes reportedly taking place just 20 kilometres from Juba on Sunday.“Salva Kiir sent a very huge force to attack our position. The attacking convoy was destroyed in a two-hour fight,” rebel spokesman Lul Ruai Koang said in a statement on the clashes near the capital.Aguer confirmed that clashes had taken place, but there was no immediate independent confirmation of who had got the upper hand.The rebel force in the region is commanded by Alfred Ladu Gore, a respected fighter from the Juba region and one of several opposition figures on a government wanted list.The rebels also claim they are close to retaking Malakal, the capital of the biggest oil-producing state Upper Nile.An AFP photographer who was in Malakal on Sunday said that the town was calm but that the remaining residents were huddled in the town centre, too scared to return to their looted homes.One month of fighting in South Sudan, which gained independence from Khartoum only in 2011, has displaced some 400,000 people, according to the United Nations.The world body put the death toll at well in excess of 1,000, although the independent think-tank International Crisis Group says reports from the field indicate the death toll is closer to 10,000.Of those forced to flee, some 350,000 are internally displaced and the remainder have fled into neighbouring countries.Humanitarian agencies trying to help the displaced have complained of obstruction.They have reported the killing of aid workers, the confiscating of vehicles and equipment at gunpoint and the looting of their premises.Meanwhile the Satellite Sentinel Project, co-founded by Hollywood star George Clooney, released images detailing what it said was “deliberate” destruction to homes and markets in two towns, Mayom in oil-rich Unity and Bor.“Evidence of atrocities against civilians should be collected and used for future prosecution for war crimes. There will be no peace if massive human rights abuses can be committed with no accountability,” Clooney said in a statement.