By Saliou Samb CONAKRY, May 10 (Reuters) - Soldiers at a barracks in Guinea's capital Conakry fired into the air on Thursday in protest against one of their senior officers, witnesses and military commanders said. Thursday's incident, which appeared to be limited to one base in the city, comes days after soldiers demanding higher wages fired volleys of shots in the air in several garrison towns around Guinea, the world's leading exporter of bauxite. "It's members of the Engineers' Battalion who are behind these shots. We've asked their commander, Colonel Cherif Diallo, not to return to the base," a senior army officer told Reuters, asking not to be named. Officers said the protest was directed against Diallo, but the reasons were not immediately clear. The shooting at the Alpha Yaya Diallo barracks on Thursday sent stray bullets raining down inside the perimeter of the West African country's main airport several hundred metres away, witnesses said. Guinea's fractious army has long suffered from ethnic and generational divisions, with younger officers keen for the old guard -- seen as being close to veteran President Lansana Conte -- moving aside to make way for new blood. Diallo is one of several officers whose houses were destroyed by rioters during demonstrations in January and February led by unions who said Conte, a reclusive diabetic in his 70s, was unfit to rule. Officials say 137 people were killed in the violence earlier this year. The unrest within the military poses a challenge to the authority of Prime Minister Lansana Kouyate's new government, formed in the wake of the strikes, after lengthy negotiations, to try to appease an angry population. At least one person was killed and around 40 injured last week when soldiers demanding salary increases shot into the air, sending bullets falling down onto the homes of terrified residents in garrison cities including Conakry, N'Zerekore, Kindia, Labe and Kankan. Kouyate went to speak with soldiers in the Alpha Yaya Diallo barracks late last week and assured them that a solution to their complaints would be found.