(Adds details, quotes from official, analysts, background)
WASHINGTON May 16 The United States warned supporters of former Yemeni President Ali Abdullah Saleh on Wednesday it may freeze their assets if they hamper the transfer of power in the Gulf nation.
President Barack Obama signed an executive order allowing U.S. authorities to sanction members of Yemen's government or others who endanger its stability, notably by obstructing a Nov. 23 deal that ultimately brought an end to Saleh's 33-year reign.
The order aims to bolster President Abd Rabbu Mansour Hadi, who has given Washington much greater latitude to attack the Yemen-based al Qaeda in the Arabian Peninsula (AQAP) group blamed for a failed Christmas Day 2009 underwear bomb attack.
U.S. officials said last week they had foiled an AQAP plot to plant a suicide bomber with an upgraded underwear bomb on an airliner bound for the United States or another Western nation.
An uprising against Saleh last year split the Yemeni armed forces into warring factions and allowed AQAP and its allies to bolster their manpower, resources and control of territory, notably in south Yemen.
The United States has stepped up its drone attacks in Yemen since Hadi replaced Saleh on Feb. 25. U.S. counter-terrorism officials say their ability to conduct operations against AQAP inside Yemen has improved significantly since Hadi's ascent.
In a message to Congress, Obama said he issued the executive order because of the "the actions and policies of certain members of the Government of Yemen and others to threaten Yemen's peace, security, and stability."
The order, however, did not identify any of the people who might find their U.S. assets frozen. U.S. officials said it aimed bolster Hadi by deterring anyone seeking to undercut his government.
"I'm not going to name names here ... but it is definitely meant today as a message to those who are trying to block a transition that we have this tool to use against them and that they should think again about the policies that they are pursuing," said State Department spokeswoman Victoria Nuland.
"SHOT ACROSS THE BOW"
"This is a shot across the bow -- using potential sanctions as a Sword of Damocles -- to help steer toward political stability in Yemen," said Juan Zarate, a Center for Strategic and International Studies analyst who served as a counter-terrorism adviser to former U.S. President George W. Bush.
Gregory Johnsen, a Yemen scholar at Princeton University, said he viewed the order as being aimed at Saleh's partisans and possibly at the former president himself and said it illustrated the mutual dependence of the United States and Hadi.
"This is the U.S. and Hadi entering into an even closer embrace," Johnsen said.
"The U.S. needs President Hadi in order to move away from President Saleh's regime so that it can do what it wants in Yemen, which is to target al Qaeda in the Arabian Peninsula," he added. "Hadi needs the U.S. because (he) himself doesn't have a very strong base of support within Yemen."
The United States appears to have a three-pronged strategy for trying to stabilize Yemen and to attack AQAP militants who hope to exploit the central government's lack of control to launch attacks against the United States and its allies.
The United States is trying to strengthen Hadi by backing his efforts to purge Saleh holdovers from the military and security apparatus. It is also providing humanitarian aid and seeking to revive the country's economy.
On the security side, the Pentagon said last week it would renew military training suspended during last year's upheaval in the hopes that Yemeni security forces will grow strong enough to reassert control over the country.
Finally, with Hadi's support, there have been increased American drone and other strikes against suspected high-value targets in Yemen who may be seeking to attack the United States. military trainers into the Gulf Arab country. (Reporting by Jason Lange and Arshad Mohammed; writing by Arshad Mohammed; Editing by Vicki Allen and Cynthia Osterman)