Shipping containers are stack beside idle cranes December 4, 2012 at... Fotografia de notíciasCalifórnia,Cidade de Los Angeles,Crise,EUA,Embarcação Comercial,Embarcação a Vapor,Entrar,Greve,Horizontal,Ilustração,Ocupação,Porto de Los Angeles,Recipiente,Semana,Sul da Califórnia,Técnica IlustrativaPhotographer Collection: AFP 2012 AFPShipping containers are stack beside idle cranes December 4, 2012 at the Port of Los Angeles in southern California as a strike by port clerical workers enters its second week. A federal mediator has been called in to try to break a strike deadlock which has crippled a key US trade hub for the last week. The strike by clerical workers at the ports of Los Angeles and Long Beach, which handle more than 40 percent of ocean-shipped US imports from Asia, is costing billions to the local and wider US economy. The White House said it was monitoring the standoff closely, and LA Mayor Antonio Villaraigosa announced the two sides had agreed to federal mediation, after he spent the night in negotiations himself. AFP PHOTO / Robyn BECK (Photo credit should read ROBYN BECK/AFP/Getty Images)