Some countries place barriers, such as on imported goods in order to restrict trade

Trade barriers

Explanation:

Trade barriers are government-induced restrictions on international trade. Economists generally agree that trade barriers are detrimental and decrease overall economic efficiency; this can be explained by the theory of comparative advantage.  Most trade barriers work on the same principle: the imposition of some sort of cost (money, time, bureaucracy, quota) on trade that raises the price or availability of the traded products. If two or more nations repeatedly use trade barriers against each other, then a trade war results. Barriers take the form of tariffs (which impose a financial burden on imports) and non-tariff barriers to trade (which uses other overt and covert means to restrict imports and occasionally exports).