Updated

A year after the U.S. raid that killed Usama bin Laden, Al Qaeda is hobbled and hunted, too busy surviving for the moment to carry out another Sept. 11-style attack on U.S. soil.

But the terrorist network dreams still of payback, and U.S. counterterrorist officials warn that, in time, its offshoots may deliver.

A decade of wars in Iraq and Afghanistan that has cost the U.S. about $1.28 trillion and 6,300 U.S. troops lives has forced Al Qaeda's affiliates to regroup, from Yemen to Iraq. Bin Laden's No. 2, Ayman al-Zawahri, is thought to be hiding, out of U.S. reach, in Pakistan's mountains, just as bin Laden was for so many years.

"It's wishful thinking to say Al Qaeda is on the brink of defeat," says Seth Jones, a Rand analyst and adviser to U.S. special operations forces. "They have increased global presence, the number of attacks by affiliates has risen, and in some places like Yemen, they've expanded control of territory."

It's a complicated, somewhat murky picture for Americans to grasp.

U.S. officials say bin Laden's old team is all but dismantled. But they say new branches are hitting Western targets and U.S. allies overseas, and still aspire to match their parent organization's milestone of Sept. 11, 2001.

The deadliest is the affiliate in Yemen.

There's no sign of an active revenge plot against U.S. targets, but U.S. citizens in Pakistan and beyond are being warned to be vigilant ahead of the May 2 anniversary of the night raid that killed bin Laden.

U.S. counterterrorist forces have killed roughly half of Al Qaeda's top 20 leaders since taking out bin Laden. That includes U.S.-born cleric Anwar al-Awlaki, killed by a drone in Yemen last September, less than six months after bin Laden's death.

Only a few of the original Al Qaeda team remain, and most of the new names on the U.S. target lists are relative unknowns, officials say.