Until relatively recent years, the continent of Africa has not been seen as a major player in the international drugs business, nor has it been a producer of the two leading drugs—cocaine and heroin. However, it is now emerging as a principal source of cannabis and has become widely implicated in the transit business between Asia and Europe and North America and, increasingly, between Latin America and Europe. The U.S. practice of certification is being extended to African countries, and those seen as drug traffickers, especially for transit purposes, may find themselves blacklisted by U.S. aid agencies. Although the process started earlier, it was during the 1990s that the African role in the carriage of narcotics expanded rapidly, with the result that a number of countries in Sub-Saharan Africa became staging points of world importance for heroin en route from Asia's Golden Triangle to the markets of North America and, to a lesser but rapidly growing extent, for cocaine from Latin America to Europe. Exports of narcotics to the Gulf states have also increased. Drug routes change all the time, depending on the effectiveness of counternarcotics campaigns, and traffickers will take shortcuts, open new routes, or revert to old tried ones when pressures relax or counter-measures are concentrated elsewhere. Certain countries, such as Ethiopia in the Horn of Africa and Kenya in East Africa, have established their positions as important staging posts for drug-trafficking activities.