By Saliou Samb CONAKRY, Feb 16 (Reuters) - Guinea's security forces are shooting, beating and robbing civilians under martial law, a rights group said on Friday, as international pressure grew for President Lansana Conte to strike a deal with opponents. The capital Conakry and upcountry towns were calm and under tight military control four days after Conte declared a state of siege to quell a popular rebellion, triggered by a general strike, against his rule over the West African state. Guinean authorities on Friday lifted martial law at the country's main bauxite mine, Sangaredi, to allow a restart of halted exports of bauxite, the economic lifeblood of the country. Guinea is the world's leading shipper of the bauxite ore from which aluminium is extracted. While martial law appeared to have largely restored order, the killings since early January of more than 120 people, mostly unarmed civilians, in clashes with soldiers and police have drawn sharp condemnation of Conte's government. "Guinean security forces are using martial law as an excuse to terrorize ordinary Guineans," Human Rights Watch's Africa director, Peter Takirambudde, said in a statement. "Under the guise of reestablishing law and order, they're acting like common criminals, beating, robbing and brutalizing the population they're supposed to protect," he added. Former colonial power France, hosting a summit of African leaders in Cannes, led calls for Conte's government to seek a peaceful political deal acceptable to all sides. "We have adopted a resolution ... firmly calling on Guinean authorities to get out of the impasse, to protect the civilian population, to launch a political process," French President Jacques Chirac told a news conference. The West African regional bloc ECOWAS said it was sending former Nigerian President Ibrahim Babangida to Guinea at the weekend to try to broker a settlement. Guinean officials sought to fend off the criticism, saying security forces had faced looters, escaped prisoners and protesters who had obtained arms smuggled into the country. "We regret the sporadic shooting by uncontrolled elements, sometimes dressed in military uniform," army chief of staff Kerfala Camara told state radio late on Thursday. CIVIL WAR RISK Opposition and union leaders say Conte, a chain-smoking general and reclusive diabetic in his 70s, is not fit to rule and should cede powers to a government led by an independent prime minister agreed on by consensus. Union negotiators pressed this point on Thursday when they met state officials to try to thrash out a solution that would end the strike and lift martial law. They demanded that Conte, who has ruled since seizing power in a 1984 coup, annul his choice last week of a close ally, Eugene Camara, to be prime minister. Some analysts have warned the heavy-handed military crackdown could lead to a possible civil war which could spread beyond Guinea's borders in a volatile region. Human Rights Watch cited witnesses in Conakry's suburbs as saying that security forces, especially the presidential guard, had searched private homes, breaking down doors and stealing cell phones, cameras, and money. "(They) have seriously beaten individuals with clubs and rifle butts, and have even shot and wounded individuals protesting the theft of their household goods," the group said. Human Rights Watch said security forces had been responsible for at least 22 killings in the past five days. It cited other credible sources as saying at least three women had been raped by uniformed personnel, including soldiers. (Additional reporting by Kirsten Gemlich in Paris)