In Nigeria, gunmen have killed 36 gold miners in the Maru area in the northwestern state of Zamfara. Police spokesman said yesterday that the attackers raided a camp of artisan miners late on Monday. <br/><br/>The gunmen stole nothing, he said, adding that the motive for the attack was unclear. Nigeria has been trying to attract investment in its nascent mining sector but insecurity and a lack of data has dampened appetite of foreign firms.