The United Nations and NGOs said Tuesday that a record 29 million people need humanitarian assistance in the Sahel, noting "unparallelled" insecurity and hunger across six countries in the war-torn African region. In Burkina Faso, northern Cameroon, Chad, Mali, Niger and north-eastern Nigeria, five million more people than last year are in need of aid, according to a statement.  Much of the semi-arid Sahel -- a vast region that stretches along the southern rim of the Sahara from the Atlantic to the Red Sea -- has been plagued by violence for years.