With American fighter jets providing cover overhead along with the force of U.S. Marines, more than 150 Americans were evacuated from Libya today.

After heavy fighting in Tripoli forced the abrupt closure of the U.S. Embassy there.

Libya has become increasingly unstable

in recent weeks, with rival militias engaged in some of the fiercest fighting since the fall

of the Mommar-Kadhafi regime. Today's exodus has large implications for the U.S.,

which helped topple Qaddafi, and then of course there is a fresh memory of the bloody

2012 attack on the American consulate in Benghazi.

The evacuation was necessary to protect the more than 150 Americans at the embassy in Tripoli.

Experts say it's the worst violence in Libya since the revolution in 2011.

It took about five hours for a caravan of 158 U.S. Embassy personnel, including 80 heavily

armed U.S. Marine Guards, to cross into Tunisia, about 100 miles away.

They left the embassy compound in SUVs and buses.

NBC's Jim McLehyshevsky reports F-16 fighter jets and unmanned drones flew overhead,

shadowing the group.

Dozens of U.S. Marines, a rapid response force in Tilt-Rotor Ospreys, were in the air,

positioned nearby to respond to any threat.

Once, safely in Tunisia, the Americans boarded commercial airliners at a civilian airport.

My name is Sarah Carlson. This is my book, In the Dark of War. It is a CIA officer's inside account of the

U.S. evacuation from Libya. If you are curious where the title came from, it came from this

quote from Thucydides in his book, The Peloponnesian War. Think too of the great part

that is played by the unpredictable in war. Think of it now,

before you are actually committed to war. The longer a war lasts, the more things tend to depend on accidents.

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