SANAA/ADEN (Reuters) - Islamist militants shot and seriously wounded a U.S. military instructor in Yemen on Sunday, while the army closed in on a town controlled by al Qaeda-linked fighters in heavy fighting that killed at least 27 people, local officials said.
A U.S. special forces commander toured the frontline in southern Yemen in a visit that highlighted the extent of Washington's support to a government fighting militants it sees as a threat not just the region but also to U.S. soil.
Four Americans, part of a team of instructors in Yemen to train the Arab country's coastguard, were in the vehicle that was attacked in the Red Sea city of Hudaida, a Yemeni coastguard officer said.
"They were leaving their hotel in a Land Cruiser when militants in another car pulled up alongside and opened fire with rifles. One was shot in the neck and the other received a bullet in his leg," he said.
Another source said only one person was wounded.
Ansar al-Sharia (Partisans of Islamic Law) said its operatives waited for the Americans as they left their hotel and then attacked, wounding three.
"The mujahideen (Islamic fighters) managed to hit three of them and, for certain, one suffered a serious injury in the neck," the group said in a statement, adding that the gunmen managed to escape the scene despite a security cordon.
The authenticity of the claim could not immediately be verified.
Ansar al-Sharia has exploited political instability in Yemen to gain a foothold in a country paralyzed for most of 2011 by protests that eventually unseated President Ali Abdullah Saleh.
In the south of the country, where Islamist militants have held swathes of territory for a year, Yemeni troops closed in on the militant-held town of Jaar, amid intense clashes in which at least 11 Islamist fighters and seven soldiers died, according to residents and local officials.
Residents said militants ambushed troops overnight and managed to hold off an army advance from the west.
On the northern edge of Jaar, a Yemeni air strike targeted a factory used as a base by militants, residents said.
One witness said a vehicle laden with at least nine bodies sped out of the burning building towards the centre of Jaar, which militants have renamed the "emirate of Waqaar".
Ansar al-Sharia said its fighters launched three raids on the army near Jaar, killing and wounding dozens of soldiers. "Those who stayed alive, fled," it said.
The Yemeni Defense Ministry said the head of U.S. Central Command's special operations force, Major General Kenneth Tovo, visited the "area of the confrontations with al Qaeda" in southern Yemen on Sunday and pledged more support for the army.
"The Yemeni armed forces will receive the necessary support that would enable it to destroy al Qaeda," the ministry's Arabic website quoted Tovo as saying.
Yemen is home to al Qaeda in the Arabian Peninsula (AQAP), which the United States has described the most dangerous branch of the network.
Saudi intelligence services said earlier this month they had foiled a plot to arm a suicide bomber with an improved version of an underwear bomb of the type that failed to explode on a 2009 U.S.-bound flight.
The United States has itself targeted militants in Yemen using drones, which have frequently killed civilians and are deeply resented by Yemenis, even the many who abhor al Qaeda.
On Sunday, it emerged that a Spanish embassy guard disappeared while driving to the airport to fly to Spain on holiday last week.
"We lost track of him on Thursday," a diplomat told Reuters.
"The only thing we know is that he never took the plane to Madrid. We don't know yet if he was kidnapped - no tribes have contacted us - but obviously it is very disturbing."
Spanish Interior Minister Jorge Fernandez Diaz told Spanish radio he was aware of the disappearance of the 38-year-old but could not give any further details.
Alarmed by the deteriorating security situation last year, the United States backed a power transfer plan that replaced Saleh with his former deputy Abd-Rabbu Mansour Hadi.
Saleh was taken to a hospital on Sunday for medical checks, a TV station owned by his party said. It gave no details.
Saleh was wounded in an assassination attempt last year that took him to Saudi Arabia and the United States for medical treatment.
Since Hadi took office earlier this year, militants have launched a series of audacious attacks, continuing to exploit disunity in the army that splintered during the uprising into pro- and anti-Saleh camps.
As well as a tenacious militancy, Hadi is also grappling with rising secessionist sentiment in the south and a Shi'ite rebellion in the north.
Additional reporting by Tom Finn in Sanaa; Writing by Isabel Coles; Editing by Sami Aboudi and Robin Pomeroy