WASHINGTON, Nov 30 (Reuters) - The Centers for Disease Control and Prevention (CDC) confirmed late Tuesday it is working to impose stricter COVID-19 testing rules for air travelers entering the United States amid concerns about a new COVID-19 variant. The CDC confirmed in a statement it is working to revise its current Global Testing Order "for travel as we learn more about the Omicron variant; a revised order would shorten the timeline for required testing for all international air travelers to one day before departure to the United States."