THREE men were killed in a pre-dawn attack by gunmen near Lubumbashi airport in a resource-rich area of southeast Democratic Republic of Congo on Friday, the army and a local rights group said."There was an attack this morning, around 2a.m (0000 GMT), very close to the airport, by a group that we cannot yet identify. At the moment, we are aware of three dead,” said Timothee Mbuya of the non-governmental organisation for human rights Justicia."Our patrol clashed last night with armed men who were not otherwise identified,” a senior officer of the DR Congo armed forces (FARDC) said. "During the exchange of fire, three men were killed: two of the assailants and one FARDC soldier. Three of the attackers were captured.”The officer said the situation was "under control”.Mbuya confirmed that calm had returned to the vicinity of the airport in Lubumbashi, chief town of the mineral-rich Katanga province and the second largest city in the vast central African country.However, members of the provincial government had gone into a security council session following the incident, an AFP journalist said."We were infiltrated a few days ago by ‘diabos’ (former Katanga paramilitary police exiled in neighbouring Angola) and they promised to attack us soon,” said a senior army officer in Katanga, who blamed the authorities for making light of the threat.In August, several sources said gunmen had killed at least two soldiers in an attack on the Lubumbashi airport.The vice-governor of the province, Gilbert Yav Tshibal, later denied there had been a raid. "There was no attack but rather shooting between ill-disciplined elements of the Republican Guard,” he said.In February 2011, a security agent was killed at the airport by suspected rebels from the Coordination for a Referendum on Self-determination for Katanga (CORAK). The rebels were repelled by the army after three hours of fighting.Katanga has been regularly shaken by the activities of secessionist movements since July 1960, when a political leader, Moise Tshombe, launched an ultimately unsuccessful secessionist bid a few weeks after the Congo gained its independence from Belgium.