The U.S. Army's 82nd Airborne Division's alert brigade has been issued orders to deploy rapidly to Kuwait amid the unrest in Baghdad, three U.S. defense officials told Fox News on Tuesday.
At least 500 paratroopers are already making their way to Kuwait, Fox News is told.
The alert brigade of roughly 4,000 paratroopers, known as the DRB -- the Deployment Ready Brigade -- has been told to pack their bags for a possible deployment in the days ahead after hundreds of Iranian-backed militiamen tried to storm the U.S. embassy in Baghdad Tuesday.
Within that alert brigade, three rifle battalions have a certain alert sequence, 18 hours, 36 hours and 54 hours for the third. The entire brigade has a 96-hour alert window to deploy.
The Pentagon is expected to issue a statement in the coming hours about the deployment.
Some of the paratroopers already have left their base in Fort Bragg, N.C., to fly overseas in Air Force C-17 cargo planes, according to officials.
The U.S. Army has kept an alert brigade of roughly 4,000 paratroopers in the 82nd Airborne for crisis response like this.
There are roughly 5,000 U.S. troops currently deployed to Iraq now, among the roughly 60,000 U.S. troops currently deployed to the region. According to the Pentagon, 14,000 have been added since May as the threat from Iran increased.
The aircraft carrier USS Harry S. Truman has been in the Gulf of Oman, its strike group armed with hundreds of Tomahawk cruise missiles in addition to the dozens of strike aircraft aboard Truman.
More than 100 U.S. Marines arrived at the U.S. embassy in Baghdad earlier Tuesday to help bolster security after the mob of Iranian-backed Shite militiamen tried to storm the U.S. embassy in Baghdad.
The crowd attacked the embassy following funerals for 25 Iranian-backed fighters killed in U.S. airstrikes Sunday in Iraq and Syria--retribution for an American defense contractor killed in Iraq Friday, according to U.S. defense officials.
Lucas Tomlinson is a Pentagon correspondent for Fox News Channel. Follow him on Twitter: @LucasFoxNews