By Barbara Starr
Under pressure from Democrats and Republicans, the Joint Staff of the Pentagon and the U.S. Central Command have updated potential military options for intervention in Syria that could see American forces - if ordered - doing everything from bombing Syrian airfields to flying large amounts of humanitarian aid to the region, a senior U.S. military official said.
The first public discussion of the updated options could come soon as Defense Secretary Chuck Hagel and Gen. Martin Dempsey, the Joint Chiefs chairman, are scheduled to testify before the Senate Armed Services Committee next week.
The military official emphasized the options are for planning and there is no indication President Barack Obama is about to order any military action.
A senior administration official confirmed that the national security staff of the White House has been briefed on the updated planning, but emphasized that it does not differ from what already has been looked at by the administration.
"We've been saying for quite some time now, we are constantly reviewing every possible option that could help end the violence and accelerate a political transition," the administration official told CNN.
Officials have declined to speak on the record because of the sensitivity of the situation.
CNN reported earlier this week that the White House had signed off on a new package of non-lethal aid for Syrian rebels fighting forces loyal to Syrian President Bashar al-Assad, according to U.S. officials.
The aid is expected to include body armor, night vision goggles and other military equipment.
But such assistance falls far short of any direct U.S. military intervention.
In a March 21 letter, Senate Armed Services Committee chairman Carl Levin, D-Michigan, and the panel's top Republican, John McCain of Arizona, asked Obama to consider "limited military options, that would require neither putting U.S. troops on the ground nor acting unilaterally."
The senators asked the White House to consider ways to "degrade the Assad regime's air power" and destroy SCUD missile batteries, using precision airstrikes.
According to the Pentagon official, one idea might be to use cruise missiles, which would keep U.S. pilots out of Syria airspace and would solve the problem of first bombing Syria's air defenses.
But the official noted aircraft and missile batteries are mobile, so it's unclear what air strikes could achieve. In addition, Syria already has turned to using its force of helicopter gunships.
The official made clear the U.S. military would be extremely cautious about sending any manned aircraft into Syrian airspace.
The United States has long said the Syrians have a massive network of air defense radars and missiles that would have to be largely destroyed by bombing before American pilots could safely fly over Syria.
Another option under review at the Pentagon is the use of military transport planes to carry additional large amounts of humanitarian assistance or nonlethal aid into neighboring countries.
Congressional calls for establishing a safe zone for displaced Syrians inside the country is also problematic, the official said.
While it may sound beneficial, the major problem is "how do you then protect it and keep Assad's forces from coming in? It gets you back to the same problem of the air defenses." The senators called for Patriot missiles in Turkey to be used in an offensive fashion to protect a safe zone in Syria, but the official said it wasn't clear how that could be done.
With regard to the idea of a no-fly zone using Patriots based in Turkey, they are a "defensive system that would have very little impact on Syrian air power when based outside the country. This would be no easy fix," the administration official said.
The military official said that overall, longstanding challenges to U.S. military action remain, including the need for an international agreement from the United Nations or NATO to act, as well as the American view that any action should include other countries.
While the initial update of options in response to congressional concerns is complete, the military official said further updating is likely.
The number of any troops, equipment, and weapons as well as the risks are laid out in each case. However, if Obama were to issue an order on one of these options, the military would engage in additional planning and intelligence gathering in order to assign specific units.