Five Kazakh policemen were jailed for between five and seven years on Monday for abusing their power during clashes between armed officers and striking oil workers in the country\'s worst violence in decades. At least 14 people were killed in the fighting that erupted in the western oil town of Zhanaozen on Dec. 16 after a seven-month strike by oilmen demanding higher wages spun out of control. The violence spread the next day to the nearby village of Shetpe, where another protester was killed. Kazakhstan, an oil-exporting nation of 16.7 million which has attracted massive investment from Western energy majors, has faced pressure from the United States and Europe to conduct a fair and transparent investigation into the clashes. But Bolat Abilov, a Kazakh opposition leader, criticised the sentence. \"There should have been many more policemen in the dock,\" he told Reuters. \"Many people were killed and more than 100 wounded. These five could not possibly have done it all.\" \"Why were they tried for abuse of power and not for murder?\" he said. Kabdygali Utegaliyev, the deputy police chief for the Mangistau region who coordinated the action in Zhanaozen, was given a seven-year jail term \"for abuse of power with the use of weapons or special devices,\" the Mangistau regional court, located in the Caspian Sea port of Aktau, said in a statement. Three other officers, found guilty on the same charges, were jailed for six years and one officer for five years. The statement did not say whether any of the men had opened fire themselves. The violence posed a serious challenge to President Nursultan Nazarbayev, who has ruled the resource-rich nation for more than 20 years through a combination of market reforms and authoritarian methods, keeping a tight lid on dissent. The prosecutor-general\'s office said in January that, in general, police had acted within legal bounds in resorting to the use of weapons after \"a group of sacked oilmen and hooligan youths committed mass disorder\". But it also said that, \"in some cases, the use of weapons and other special devices by the police was disproportionate\". An Aktau court this month jailed another police officer for five years after finding him guilty of holding people illegally in a detention centre in Zhanaozen. Last week, a separate court cleared six people of rioting in Shetpe, where a large group of people supporting striking oilmen stopped a passenger train and set a locomotive on fire. Four in the Shetpe trial were jailed for between four and seven years, one was given a suspended sentence and a sixth was freed under an amnesty. Another trial of 37 people charged over the violence in Zhanaozen has still not announced a verdict. The charges include the organisation of mass disorder, arson, destruction of property and use of violence against the state. Members of Kazakhstan\'s disparate opposition have said this hearing could set the tone for the upcoming trial of around 18 political activists due to stand trial during the summer accused of fomenting \"social hatred\" among striking oilmen. If found guilty, each may face between seven and 12 years in jail.