* Troops bombard rebel area, prepare to enter stronghold
* Part of US-backed offensive on al Qaeda
* Month-long operation has left thousands trapped
(Updates death toll, adds detail)
ADEN, Yemen, June 11 (Reuters) - Yemeni warplanes and troops
bombarded the Islamist militant stronghold of Jaar on Monday,
officials and witnesses said, part of a U.S.-backed offensive in
a country Washington sees as a front line in its war against al
Qaeda.
At least 44 soldiers and militants were killed as the army
launched its most serious assault on Jaar to date and also
attacked positions near Shaqra, a coastal town on a major
shipping route, and other areas, a Yemeni military official told
Reuters.
Yemen is battling to retake towns and territory in the
southern province of Abyan that were seized by militants linked
to al Qaeda last year during a popular uprising against
President Ali Abdullah Saleh.
Washington, which helped engineer Saleh's replacement by his
deputy, is supporting the campaign and has increased drone
strikes on suspected al Qaeda members it believes may be
plotting attacks from Yemen.
It has also sent dozens of military trainers and increased
aid to Yemen where it wants President Abd-Rabbu Mansour Hadi to
reunify the military and focus it against al Qaeda.
"The military has just started an assault from three
different fronts in an attempt to enter Jaar," a military
official said, adding armed tribesmen were supporting the
troops.
The army fought militants overnight into Monday morning,
driving them out of small villages and killing at least 28
fighters and six soldiers, the official said.
The official said he did not expect the army to entre the
town on Monday because the feared the militants might have
booby-trapped most of the surrounding roads.
Residents told Reuters the army used warplanes and artillery
to attack the town centre.
The army was also gearing up to try to take the southern
coastal town of Shaqra, the official said, adding eight
militants and two soldiers were killed in clashes near the town.
Shaqra is a gateway for Somalis entering Yemen to fight
alongside al Qaeda.
The military's offensive has cut off supplies of food and
medicine and forced thousands to flee their homes, the
International Committee of the Red Cross (ICRC) said last week.
Tens of thousands were trapped inside towns like Jaar and
Shaqra, the ICRC said.
Concerned about the humanitarian and security crisis in
Yemen, Gulf Arab states and the West pledged more than $4
billion in aid to the impoverished state last month.
Separately, a Saudi Arabian national, Nasser Abdulaziz
al-Mahiri, who was kidnapped six months ago by tribesmen in
north Yemen, was released on Sunday after tribal mediation,
Yemen's state news agency Saba said on its website.
Kidnappings of foreigners and Yemenis are common in the
impoverished Arabian Peninsula state, where hostages are often
used by disgruntled tribesmen to press demands on authorities.
(Reporting by Mohammed Mukhashaf in Aden and Mohammed Ghobari
in Sanaa; Writing by Rania El Gamal and Mahmoud Habboush;
Editing by Andrew Heavens)