The rise in the number of children orphaned by HIV/AIDS in Zambia has forced the World Food Programme (WFP) to scale up its assistance programmes in some of the country's urban centres. WFP information officer Lena Savelli told IRIN on Monday that although food security in Zambia continued to improve, there was growing concern over the plight of vulnerable children, most of whom were left to support households after the death of a parent.