By Alexandra Alper WASHINGTON (Reuters) -President Joe Biden’s administration added five companies in China to a trade blacklist on Tuesday for allegedly supporting Russia’s military and defense industrial base, flexing its muscle to enforce sanctions against Moscow over its invasion of Ukraine. The Commerce Department, which oversees the trade blacklist, said the targeted companies had supplied items to Russian “entities of concern” before the Feb. 24 invasion, adding that they “continue to contract to supply Russian entity listed and sanctioned parties.” The agency also added further 31 enti…