Arlington National Cemetery is tightening its security protocols and warning visitors to report suspicious activity in the wake of a U.S. strike that killed Gen. Qasem Soleimani, head of Iran's elite Quds force. In a series of tweets Jan. 3, Arlington staff announced that the cemetery, located by the Pentagon and across the Potomac from Washington, D.C., is implementing 100% identification checks at all entrances. Read more on Military.com.