Libya's government has sent troops to put an end to six days of clashes between rival armed groups in the west of the country. The fighting, which left least 16 people killed and scores of others injured, is the latest episode of instability eight months since the collapse of Muammar Gaddafi's regime after a months-long conflict. As it seeks to impose its authority on a fractious country, Libya's new leadership on Saturday called for an immediate ceasefire in the fighting south of the capital Tripoli.