The authorities in Ivory Coast say they have foiled a plot to overthrow the government organised by supporters of former President Laurent Gbagbo. The interior minister said arrests had been made and documents seized. He said the coup plotters were linked to Liberian mercenaries and Ivorian militias who were accused of killing seven UN peacekeepers last week. Mr Gbagbo is awaiting trial in The Hague in connection with last year's dispute when he refused to stand down. The violent four-month stand-off ensued when he refused to concede victory in December 2010 to the internationally recognised winner of election, Alassane Ouattara. The news of the coup plot comes as a further four people were killed on Tuesday close to the border with Liberia as the UN continues to track down an armed group behind the UN killings last Friday. Video confessions Interior Minister Hamed Bakayoko's revelations, made in an interview on national television, follow the arrest last week in Togo of a key ally of Mr Gbagbo, Moise Lida Kouassi. Mr Kouassi, once a defence minister, was extradited to Ivory Coast and during questioning admitted having information about the coup plot, planned for earlier in the year. Part of his video-taped confession was also shown on Ivorian television. "The documents that were seized during my arrest at my house in Lome did concern a transition and a crisis communication in Ivory Coast," he said. Mr Bakayoko also played a recorded video with senior members of Mr Gbagbo's presidential guard, soldiers from the south-west of the country, in which they announced a coup to sweep away Mr Ouattara's government. The BBC's John James in Abidjan says the speaker, Col Kate Gnotua, is now under arrest, captured when coming into the country a few months ago. According to the minister, Col Gnotua has admitted that the presidential security team were behind the assassination of former President Robert Guei, his family and domestic staff in September 2002 when a failed coup plot became a civil war. Mr Bakayoko said there would be more arrests in the coming days and he appealed for such scheming to stop. "It's the same logic that we saw prolong the crisis - when the whole world said that things were finished, they were still in the bunker thinking that they could still come out on top. Again today, with the dynamism in the country reinforced by friendly countries and the UN mission, they still think it's possible to attempt certain things," he said. UN peacekeepers were deployed to Ivory Coast in 2004 to help end the country's civil war and have stayed through the country's recent political crisis. Last week, US-based campaign group Human Rights Watch published a report saying militants loyal to Mr Gbagbo based in Liberia had killed at least 40 people in cross-border raids since last July.