ABC News reported the disappearance of the missiles from unguarded warehouses has raised concerns al-Qaida, which is active in Libya, could get hold of them.
"Matching up a terrorist with a shoulder-fired missile, that's our worst nightmare," said Sen. Barbara Boxer, D-Calif.
Peter Bouckaert, emergencies director for Human Rights Watch, first warned about the weapons being taken after a trip to Libya six months ago. A few weeks ago, ABC News said, he photographed pickup trucks hauling missiles away.
"I myself could have removed several hundred if I wanted to, and people can literally drive up with pickup trucks or even 18-wheelers and take away whatever they want," Bouckaert said.
He said officials are concerned "some of these missiles could end up in the wrong hands."
"I think the probability of al-Qaida being able to smuggle some of the stinger-like missiles out of Libya is probably pretty high," said Richard Clarke, a former White House counter-terrorism adviser who is now consultant to ABC News.
The missiles are 4 to 6 feet long and can weigh 55 pounds each with a launcher. They work by targeting the heat generated by an aircraft's engine and and can be fired from a vehicle or shoulder and are accurate from more than 2 miles away, ABC said.
The State Department says more than 40 civilian planes worldwide have been hit by surface-to-air missiles since the 1970s.
Boxer called for Congress to give wide-bodied passenger jets that fly overseas the same protection from the missiles military aircraft have. It would cost about about $1 million per plane to do so, she said.
"For us to sit idly by and not do anything when we could protect 2 billion passengers over the next 20 years (with) a relatively small amount of money (from) the Department of Defense, I think that's malfeasance," Boxer said.
Tommy Vietor, spokesman for the National Security Council, said five specialists have been sent to Libya to help the interim government, the Transitional National Council, recover and destroy surface-to-air missiles. A State Department expert is helping the Libyans develop a "control-and-destruction program" for the missiles, Vietor said.