The U.S. State Department has ordered its "non-essential citizen employees" to leave the Somali capital of Mogadishu, three weeks after a dual bombing claimed at least 400 lives in what a Somali official called the country's "9/11."

In a security message Saturday, the State Department said it had "specific threat information" against U.S. personnel at the Mogadishu International Airport.

"The security situation in Somalia is extremely unstable, and the threat to all U.S. citizens in Somalia remains critical," the alert said.

On Oct. 14 two bombs exploded in Mogadishu's downtown, leveling two city blocks and leaving "an enormous crater near one of the city's main intersections," according to a the State Department's official blog. Somali Police Force Deputy Commissioner Gen. Bashir Abdi Mohamed is quoted as having described the attack as Somalia's "9/11" and said that it touched everyone of his countrymen. Just a week later, another attack at a hotel in Mogadishu reportedly killed 23 people.

Al Shabaab, an al Qaeda-affiliated terrorist group, claimed responsibility for the second attack, but not the more devastating Oct. 14 bombing. Security officials in Somalia purportedly blamed both on the terror group.

The State Department said that the high casualty count and barbarity of the Oct. 14 bombing appears to have turned some al Shabaab sympathizers against the terror group, "with some reaching out to law enforcement with tips about the organization."

ISIS is also reportedly active in Somalia. On Nov. 3, a day before the State Department alert to U.S. officials there, the U.S. military launched its first-ever airstrikes against ISIS targets in Somalia "killing several terrorists."

Somali police have been extraordinarily busy in response not just to the most recent attack, but to scores of others over the last few years. The State Department reported that since the Somali police's Joint Investigative Teams were established in 2014, they have responded to "over 250 major incidents."