Yemen is the new big word in America's fight against terrorism - home to al-Qaeda's regional base, and a weak central government that's tried and failed to stamp it out. Recently, the training ground for botched airline bomber Umar Mutallib.
"We're working very closely with the Yemeni authorities to address the threat that is out there. But again, it just demonstrates that al-Qaeda is determined to carry out these attacks and we're determined to thwart those attacks," said John Brennan, Deputy National Security Advisor.
A day after General David Petraeus visited the country and met with the Yemeni president - the U.S. and British embassies were shut down, citing ongoing threats from al-Qaeda. Yemen has a special place in the history of al-Qaeda. Osama Bin Laden's family is from there and it was the scene of the 2000 bombing of the USS Cole, in which 17 American sailors died. Now terrorists are believed to be flooding into the country seeking safe haven from U.S. air strikes in Pakistan and Afghanistan.
"One of our American personnel there said to us -- and I thought quite wisely -- that Iraq is yesterday's war, Afghanistan is today's war, and if we don't act preemptively, Yemen will be tomorrow's war," said Senator Joe Lieberman, (I) Connecticut.
Analysts say some of the fighters are coming from Saudi Arabia, others previously released from Guantanamo Bay.
"These are people that were held in Gitmo and have been returned and have now gone back to the battlefield," said Rep. Peter Hoekstra, (R) Michigan.
That's raised controversy over plans to release the 90 remaining Yemenis. But president Obama's top terrorism advisor says the transfers will proceed on a case by case basis and nothing would be done to put Americans at risk.