An Iranian worker walks in the partially constructed site which is part of South Pars gas field, on the northern coast of Persian Gulf, in Assalouyeh, Iran, Monday, July 19, 2010. The engineering arm of Iran's powerful Revolutionary Guard, which was recently hit by U.N. sanctions, has partially withdrawn from developing the giant South Pars natural gas field, the Oil Ministry announced on Friday July 16. The giant offshore field in the Persian Gulf, which is shared by Iran and Qatar, holds an estimated 1,800 trillion cubic feet (50.97 trillion cubic meters) of natural gas.