The United States plans to enforce strict new security rules on Feb. 2 for imports by sea in containers, despite complaints from many shippers that they are not ready, an American official said here today. Drafted in response to the Sept. 11 attacks, the rules are aimed at reducing the risk that a nuclear bomb or other bulky weapon of mass destruction could be shipped to the United States. But exporters in Hong Kong in particular have been warning of delays and possible chaos at docks and warehouses because of the rules. Full Story