Since 12:01 a.m. Friday (4:01 a.m. GMT), about 60 countries have been subject to additional tariffs of 10% or 12.5% on certain products entering the United States under what Washington says is an effort to combat forced labor. Among the countries, which account for 99.4% of U.S. imports, are seven African nations. The exemption of certain products, including hydrocarbons and fertilizers, from the surcharges is expected to limit the impact on some countries on the continent.