(Reuters) - A militant who acted as a senior operations organizer for al-Qaida was targeted and killed in one of two U.S. drone strikes launched against targets inside Pakistan last week, a U.S. official said Thursday.

U.S. and Pakistani sources told Reuters the target of the attack was Aslam Awan, a Pakistani national from Abbottabad, the same town where Osama bin Laden was killed last May by a U.S. commando team. They said he was targeted in a strike by a U.S.-operated drone on Jan. 10 directed at what news reports said was a compound near the town of Miranshah in the border province of North Waziristan.

That strike broke an undeclared eight-week hiatus in attacks by the armed, unmanned drones that patrol Pakistan's tribal areas and are a key weapon in U.S. President Barack Obama's counter-terrorism strategy.

The sources described Awan, who also was known by the nom-de-guerre Abdullah Khorasani, as a significant figure in the remaining core leadership of al-Qaida, which U.S. officials say has been sharply reduced by the drone campaign. Most of the drone attacks are conducted as part of a clandestine CIA operation.

Pakistani officials could not confirm that Awan was killed in the drone attack, but the U.S. official said he was.

One of the sources described Awan as an associate of al-Qaida's current chief of external operations, whose identity is known to intelligence officials but not to the general public.

Aslam Awan was a senior al-Qaida external operations planner who was working on attacks against the West. His death reduces al-Qaida's thinning bench of another operative devoted to plotting the death of innocent civilians, a U.S. official said.

Several previous alleged chiefs of external operations for al-Qaida have been caught or killed in drone attacks or counter-terrorism operations, the most notorious being Khalid Sheikh Mohammed, alleged mastermind of the Sept. 11, 2001 attacks. Mohammed was captured and is being held by U.S. authorities in the Guantanamo Bay, Cuba prison.

Because their role in arranging operations involves interacting with militants in the field, external operations chiefs have found themselves more vulnerable to exposure and counter-attacks by security forces than the movement's most senior leaders, who until bin Laden's demise last year appeared to be able to move about the region and issue provocative audio and video messages with near-impunity.

A Pakistani security source based in the country's border region said Awan was the remaining member of an al-Qaida cell Pakistani authorities have been trying to roll up since 2008.

We thought he was very close to Ayman al-Zawahiri, the source said, referring to al-Qaida's current leader and bin Laden's long-time deputy, a former Egyptian doctor.

However, a U.S. source said that American experts did not believe that Awan was particularly close to al-Zawahiri.

The drone strike that targeted Awan was one of two such attacks last week, in what U.S. sources indicated was a resumption of the U.S. drone campaign following the eight-week pause. In the other drone strike, also in North Waziristan, a group of foreign fighters sympathetic to the Taliban and al-Qaida, some of Uzbek ethnicity, were targeted Jan. 12.

MILITANTS HIT NEAR BORDER

The targeted militants were believed to be travelling, possibly in preparation for an operation near Pakistan's border with Afghanistan, and some were injured or killed in the attack, the U.S. source said.

U.S. officials said they could not confirm news reports, based on claims from Pakistani sources, that Hakimullah Mehsud, leader of the TTP, Pakistan's most potent domestic affiliate of the Taliban movement, was also killed in the June 12 attack. Pakistani and U.S. sources said that Mehsud was not targeted in the drone strike, and one Pakistani source said: He is alive. Hakimullah is alive.

U.S. officials insisted that the drone strike lull did not represent an official moratorium on such operations by the Obama administration. The officials maintained that any fall-off in the pace of such operations was related to the availability of intelligence and operating conditions, such as weather.

However, some officials did privately acknowledge that the drone lull was at least in part calculated to try to improve strained relations between Washington and Islamabad, which had been on a downswing for much of last year in the wake of Pakistan's detention of a CIA operative and the secret U.S. commando raid on bin Laden's Pakistani hideout.

Relations plummeted to a new low following a late November incident in which 24 Pakistani troops were killed accidentally in a NATO aerial attack on border outposts.

Some U.S. and Pakistani officials say that both governments are making efforts to improve relations. As part of this process, a U.S. official said, it is possible that some permanent tweaks could be made in the U.S. drone program which could slow the pace of attacks.

(Reporting by Mark Hosenball in Washington and Christopher Allbritton in Islamabad; Editing by Eric Walsh)