* Air strikes came after Yemen beefed up security in Sanaa
* Increased security prompted by reports of planned car bombs
* U.S. maintain “extremely high” level security threat for Yemen
By Mohammed Ghobari and Mohammed Mukhashaf
SANAA/ADEN, April 5 (Reuters) - Airstrikes killed 10 suspected Islamist militants in southern Yemen on Thursday, an official said, and authorities boosted security at foreign missions and government sites in Sanaa over a warning al Qaeda planned car bomb attacks in the capital.
A local official in southern Abyan province, partly controlled by an al Qaeda-linked group, said Yemeni warplanes launched two strikes at Islamist targets in the village of Umm al-Jabalayn, near the militant stronghold city of Jaar.
The official said at least 10 militants were killed in the attack. Jaar residents said they saw members of the group, Ansar al-Sharia members bringing bodies back to the city for burial.
The reported strike is near an area where Ansar al-Sharia last week said it killed at least 20 Yemeni soldiers.
In Sanaa, Reuters witnesses said paramilitary Central Security Service personnel had been deployed across the capital, especially in the diplomatic quarter in the south of the city.
Suspicious cars were being stopped at makeshift checkpoint for spot searches, they said.
The Interior Ministry ordered heightened security near government buildings and foreign missions, “to deal with any potential act of sabotage and terrorism,” according to a statement posted on its website.
“We have received information concerning plans by al Qaeda to move its operations to Sanaa,” a security official told Reuters. “We believe it is preparing to carry out these operations using car bombs any time soon,” he added.
Yemen has a seen a surge in violence in the south since President Abd-Rabbu Mansour Hadi took office in late February, vowing to fight Islamist militants who expanded their footprint during political turmoil over the fate of Hadi’s predecessor.
Mass protests aimed at ending the 33-year rule of Ali Abdullah Saleh, long a key figure in Washington’s fight against al Qaeda, erupted in early 2011. The demonstrations were compounded by fighting within an army divided between Saleh’s foes and allies.
Washington, which has indicated it wants to see Hadi reunify the military to fight the Islamists, backed Saleh’s succession under a deal engineered by top oil exporter Saudi Arabia, which fears chaos in Yemen could spread across its border.
Most attacks have been concentrated on southern Yemen, where most of Ansar al-Sharia’s forces are concentrated.
In their deadliest attack yet, militants killed at least 110 soldiers and took dozens hostage on March 4 in the Abyan provincial capital, Zinjibar.
The government responded with air strikes and the United States has repeatedly used drones to attack militants. Last year it used a CIA drone to assassinate a U.S. citizen whom prosecutors later said plotted an abortive attack abroad.
In its directive, the Interior Ministry ordered security forces in Sanaa and surrounding rural areas to step up efforts “to seize wanted people and suspicious vehicles”. (Writing by Sami Aboudi)