The U.S. has shut its embassy in Kyiv, citing a potential and significant air attack from Russia. “The US Embassy in Kyiv has received specific information of a potential significant air attack on November 20. Out of an abundance of caution, the Embassy will be closed, and Embassy employees are being instructed to shelter in place," a statement read. The warning comes a day after Ukraine used U.S.-made ATACMS to strike Bryansk region, deep inside Russian territory, and after Vladimir Putin lowered Russia's nuclear threshold. Watch for more.