Nepal's most substantive international relations are perhaps with international economic institutions, such as the Asian Development Bank, the International Monetary Fund, the World Bank, and the South Asian Association for Regional Cooperation, a multilateral economic development association. Nepal also has strong bilateral relations with major providers of economic and military aid, such as France, Germany, Japan, Malaysia, South Korea, Switzerland, the United States, and particularly the United Kingdom, with whom military ties date to the nineteenth century. The country's external relations, barring relations with India and China, are primarily managed by its Ministry of Foreign Affairs while relationship with India and China, Nepal's most important partners, is still managed by the Prime Minister's Office. Nepal's relation with China has seen a major upswing in the recent years with China now becoming Nepal's 3rd largest aid donor (after the UK and Japan), and the largest source of FDI to Nepal.