(This story published on March 3 has been refiled to remove an extraneous word in byline.)
By Phil Stewart and Mohammed Mukhashaf
WASHINGTON/ADEN, Yemen (Reuters) - The United States carried out a second day of air strikes against al Qaeda in Yemen on Friday, U.S. officials said, in the latest sign of increasing U.S. military focus on a group whose strength has grown during Yemen's civil war.
Since a January commando raid, the United States has shown a desire to both strike al Qaeda in the Arabian Peninsula (AQAP) and to recover from what U.S. officials acknowledge has been an intelligence shortfall about the group since Yemen's civil war forced the closure of the U.S. Embassy in 2015.
"We have a lot of gaps in our understanding of the organization," a U.S. defense official said, adding the pullout of U.S. personnel two years ago "certainly did not help our understanding of the situation."
Pentagon spokesman Captain Jeff Davis said at a news briefing that the United States had carried out more than 30 strikes over the past two days in Shabwah, Abyan and Al Bayda provinces.
The U.S. military did not disclose how many al Qaeda fighters were killed on Friday although Reuters reported that Thursday's strikes, using manned and unmanned aircraft, left at least nine militants dead.
The U.S. military did not rule out further strikes in the days ahead.
"I don't want to telegraph future operations but this is part of a plan to go after this very real threat and ensure they are defeated," Davis said at a Pentagon news briefing.
VITAL INTELLIGENCE?America's military strategy in Yemen has become a political lightning rod issue after the late January raid against AQAP, authorized by President Donald Trump, resulted in the death of one of the commandos, U.S. Navy SEAL William "Ryan" Owens.
Critics questioned the value of the mission. That prompted a fierce rebuttal from Trump, who said during a televised address to Congress that "large amounts of vital intelligence" was seized in the operation. Trump's speech featured a standing ovation for Owens' widow.
The U.S. defense official, who spoke to reporters on condition of anonymity on Friday, shied away from describing the intelligence as "vital," saying that was a subjective term.
The official said the intelligence was "good" and "potentially actionable," suggesting that phone numbers and other information about AQAP's network seized in January would require analysis or development before leading to new U.S. strikes or raids.
"It's definitely helping us understand the network and further develop it out ... This has been good information," the official said, adding the United States seized "an awful lot of telephone numbers."
Strikes over the past two days have not been based on intelligence from the January raid, the Pentagon says.
After its pullout in 2015, the U.S. military started returning to Yemen in small numbers last year to support a successful April push orchestrated by the United Arab Emirates, with support from Saudi Arabia, that ejected AQAP from Mukalla, home of Yemen's third largest port, where AQAP had raised tens of millions of dollars.
The U.S. defense official said losing Mukalla degraded AQAP but also cautioned the group did not leave its money or many of its recruits behind.
Residents told Reuters on Friday that U.S. air strikes were accompanied by gun battles, which they thought involved U.S. soldiers on the ground in Yemen.
The Pentagon denied U.S. involvement in any ground combat and it was unclear if one of the United States' Gulf allies might have been engaged in gun battles.
U.S. intelligence and military officials still view AQAP as a real threat to the United States, as do allies like the United Arab Emirates and Saudi Arabia.
The group has plotted to down U.S. airliners and claimed responsibility for 2015 attacks on the office of Charlie Hebdo magazine in Paris. AQAP also has boasted of the world's most feared bomb makers, Ibrahim Hassan al-Asiri, and the Pentagon estimates it has between about 2,000 and 3,000 fighters.
The defense official said the group was well armed and U.S. strikes since Thursday have included AQAP's heavy weapons."We would expect that they certainly have light anti-aircraft and they possibly have MANPADS, that is a possibility we have seen," the official said, referring man-portable air defense systems.
Davis noted that al Qaeda, even more than the Iraq- and Syria-based Islamic State, had U.S. blood on its hands.
In 2000, al Qaeda bombers steered a boat full of explosives into the side of the USS Cole, a U.S. Navy destroyer, while it refuelled in the Yemeni port of Aden, killing 17 U.S. sailors and wounding about three dozen others.
(Writing by Katie Paul and Phil Stewart; Reporting by Mohammed Mukhashaf in Aden and Phil Stewart and Idrees Ali in Washington; Editing by Bill Trott and James Dalgleish)