Afghan President Hamid Karzai promised Thursday to use Japanese aid effectively to restore peace and stability in his country, as he sought to allay Tokyo's concerns that its support may be wasted on his corrupt and faltering government. Tokyo announced in November a five-year pledge of $5 billion to help the war-torn nation strengthen its police force as well as support agriculture and infrastructure projects. The Japanese have abandoned a refueling mission that supported troops in Afghanistan and now only offer humanitarian support. Japan is one of Afghanistan's biggest donors, but there has been no indication additional aid will be forthcoming on Karzai's five-day visit. Instead, Karzai is seeking to convince Tokyo that his government will use money already promised well.