The discovery of two explosive-laden packages from Yemen bound for U.S. destinations appears to represent a new twist in the terror threat emanating from the violence-wracked Mideast country.

If the explosive devices shipped in cargo planes from Yemen are conclusively linked by investigators to the al-Qaida faction in Yemen, it could represent a new tactic by Al-Qaida in the Arab Peninsula. The group has previously spawned plots against commercial U.S-bound flights and had a role in mass shootings in several American cities.

_ In the past 18 months, the al-Qaida offshoot in Yemen has grown stronger, and its members have been implicated in several plots against U.S. targets, including the Christmas Day airliner attack in Detroit.

_ Next to Osama bin Laden and his al-Qaida leaders in Pakistan, al-Qaida in the Arabian Peninsula is considered the most active al-Qaida threat to the U.S. and its Western allies, according to the Obama administration.

_ The U.S. has beefed up its military and intelligence assistance to Yemen, including the potential addition of armed Predator drones operated by the CIA. The Pentagon is sending more than $150 million in military aid, including helicopters, planes and other equipment.

_ There have been a number of airstrikes into Yemen that have taken out insurgent leaders, with either coordination from the U.S. or direct involvement, but officials decline to talk about them.

_ AQAP includes as many as 300 members operating out of Yemen. A key leader is Anwar al-Awlaki, the American-born radical cleric who is believed to have helped plan the Christmas Day attack and inspired other attacks, including the shooting massacre at Fort Hood, Texas, last year. He is on a U.S. government secret list of targets to be captured or killed.

_ Over the past year, the number of elite U.S. trainers moving in and out of Yemen has doubled, from 25 to about 50 now. And the U.S. forces are providing more complex instruction that combines tactical ground and air operations.

_ Yemen is the poorest country in the Arab world, with 45.2 percent living below the poverty line, according to the CIA factbook.