It's not only hostility over the Kosovo crisis, the attack on China's Belgrade Embassy, and charges of espionage that are straining relations between Washington and Beijing. Growing dependence on oil imports is spurring Chinese diplomatic efforts in the Middle East, a region the U.S. keenly courts for the same reason. China plans to invest in an Iraqi oil field as soon as the UN lifts sanctions. Imported oil is becoming more important as output from existing oil fields in China is dwindling and recent local discoveries have proved disappointing. What's more, China is cooperating with Russia to exploit huge gas fields in Siberia with pipelines to transport the gas to Beijing and the rest of northern China. China will need to import 40% of its oil by 2010, twice as much as now, according to the China Economic Times in Beijing.