France says, its forces in West Africa have killed more than 20 militants in Mali near the border with Burkina Faso. French military officials said the operation was launched after killing of a French soldier in the area earlier this month. <br/><br/>France, the former colonial power in Mali, has deployed about 4,000 soldiers across Mali, Burkina Faso, Chad, Mauritania and Niger combating Islamist extremists. <br/><br/>Mali has extended a state of emergency for another six months as it tries to stave off an al-Qaida-linked insurgency in the north, and extremists launching attacks from Burkina Faso in the south.