The U.S. State Department is warning Americans about potential attacks in response to the drone strike that killed al Qaeda leader Ayman al-Zawahiri in Afghanistan. As CBS senior investigative correspondent Catherine Herridge explains on "CBS News Mornings," that attack was made possible by a high-tech drone and extensive intelligence efforts. CBS News Streaming Network is the premier 24/7 anchored streaming news service from CBS News and Stations, available free to everyone with access to the Internet. The CBS News Streaming Network is your destination for breaking news, live events and original reporting locally, nationally and around the globe. Launched in November 2014 as CBSN, the CBS News Streaming Network is available live in 91 countries and on 30 digital platforms and apps, as well as on CBSNews.com and Paramount+. Subscribe to the CBS News YouTube channel: http://youtube.com/cbsnews Watch CBS News: http://cbsn.ws/1PlLpZ7c Download the CBS News app: http://cbsn.ws/1Xb1WC8 Follow CBS News on Instagram: https://www.instagram.com/cbsnews/ Like CBS News on Facebook: http://facebook.com/cbsnews Follow CBS News on Twitter: http://twitter.com/cbsnews Subscribe to our newsletters: http://cbsn.ws/1RqHw7T Try Paramount+ free: https://bit.ly/2OiW1kZ For video licensing inquiries, contact: [email protected]