The United States said it had advised U.S. airlines to take steps to operate safely over the East China Sea as it tries to determine whether China's new airspace defense zone rules apply to civil and commercial aircraft. "We're attempting to determine whether the new rules apply to civil aviation and commercial air flight," State Department spokeswoman Jen Psaki told a daily briefing. "In the meantime U.S. air carriers are being advised to take all steps they consider necessary to operate safely in the East China Sea," she added. (Reuters)