UPDATE 1-Al Qaeda decline hard to reverse after Bin Laden killing-U.S.

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WASHINGTON, July 31 (Reuters) - Osama bin Laden's death sent

al Qaeda into a decline that will be hard to reverse, the United

States said on Tuesday in a report that found terrorist attacks

last year fell to their lowest level since 2005.

Describing 2011 as a "landmark year," the United States said

other top al Qaeda members killed last year included Atiyah Abd

al-Rahman, reportedly the militant organization's No. 2 figure

after bin Laden's death, and Anwar al-Awlaki, who led its lethal

affiliate in Yemen.

"The loss of bin Laden and these other key operatives puts

the network on a path of decline that will be difficult to

reverse," the State Department said in its annual "Country

Reports on Terrorism" document, which covers calendar year 2011.

The report attributed the killings, which included the May

2011 raid in which U.S. commandoes shot bin Laden in Pakistan,

to improved cooperation on counterterrorism. But it also said al

Qaeda is adaptable and poses "an enduring and serious threat."

While saying there were no terrorist attacks in the United

States last year, the report said the U.S. government remains

concerned about "threats to the homeland," citing the foiled

2009 Christmas Day attempt by the Nigerian "underwear bomber"

who sought to blow up a Detroit-bound aircraft.

The report included a statistical annex prepared by the

National Counterterrorism Center, part of the U.S. intelligence

community, that showed that the overall number of terrorist

attacks worldwide fell to 10,283 last year from 11,641 in 2010.

The number of worldwide fatalities fell to 12,533 last year

from 13,193 the year before, according to the statistics, which

NCTC issued in a report published on June 1.

That was the lowest level since 2005, when there were more

than 11,000 attacks and more than 14,000 fatalities. The general

decline in terrorism-related fatalities - which peaked at more

than 22,000 in 2007 - reflects, in part, less violence in Iraq.

The State Department report said that as al Qaeda's "core

has gotten weaker," affiliated groups have gained ground, citing

al Qaeda in the Arabian Peninsula as a particular threat and

voicing concern about al Qaeda in the Islamic Maghreb.

It also reported an increase in terrorist attacks in Africa,

due largely to Nigeria's Boko Haram militant group, as well as

in the Western Hemisphere, which it attributed chiefly to FARC

insurgents in Colombia.

Daniel Benjamin, the State Department's coordinator for

counterterrorism, said last year was also significant for the

"Arab Spring" of popular protests and what he described as its

rebuff to al Qaeda's ideology.

"We saw millions of citizens throughout the Middle East

advance peaceful public demands for change without any reference

to al Qaeda's incendiary world view," he said, adding upheavals

also present risks.

"Revolutionary transformations have many bumps in the road,"

he added. "Inspiring as the moment may be, we are not blind to

the attendant perils."

(Reporting by Arshad Mohammed; Editing by Cynthia Osterman and

Stacey Joyce)