LONDON, April 9 (Reuters) – Aluminium prices soared on Monday to their highest in nearly four weeks after the United States imposed sanctions on Russian company Rusal, one of the world’s largest producers of the metal. Benchmark aluminium on the London Metal Exchange was up 3.1 percent at $2,106 a tonne from an earlier $2,124, its highest since March 14. It has gained nearly 7 percent since the sanctions were announced on Friday. “This is a further hit to Russian aluminium exports to the U.S. They come after the tariffs (U.S. President Donald) Trump introduced in March,” Julius Baer analyst Carsten Menke said.  “There is uncertainty about how this might affect other countries which are using Russian-produced aluminium.” SANCTIONS: Washington imposed sanctions on seven Russian oligarchs, including Rusal’s former president Oleg Deripaska, 12 companies they own or control, as well as 17 senior Russian government officials. TARIFFS: The United States last month imposed a 10 percent levy on aluminium imports. Some countries including Canada have been exempted, but Russia is not exempt. ALUMINIUM: Rusal produced 3.7 million tonnes of aluminium last year, which according to brokers Argonaut is about 7 percent of the world total. Rusal says exports to the United States account for over 10 percent of its output. EXPENSIVE: “Rusal may find it more difficult to do business given that it is the second-largest supplier of aluminium to the U.S. after Canada,” analysts at BMO Capital Markets said. “Furthermore, given the attempt to limit even non-U.S. citizens from facilitating transactions it is possible that activities as simple as exchanging currencies may become more expensive for Rusal given the international scope of its operations and sales being priced in U.S. dollars.” SHARES: Rusal shares are down more than 50 percent. TECHNICALS: Resistance comes in at $2,135, where the 55- and 100-day moving averages meet. Support is at $2,060, near the 21-day moving average. TRADE: Trump predicted on Sunday that China would take down its trade barriers, expressing optimism despite escalating trade tensions between the world’s two largest economies that have roiled global markets. The two countries have threatened each other with tens of billions’ worth of tariffs in recent days and Chinese officials have said this is not the time for negotiations. PRICES: Copper was up 0.7 percent at $6,814 a tonne, zinc was down 0.2 percent at $3,224, lead lost 0.3 percent to $2,385, tin fell 0.1 percent to $21,040 and nickel ceded 0.3 percent to $13,230.