A SUICIDE car bomber targeting an army checkpoint in southern Yemen killed eight soldiers and wounded 10 on Monday, local officials said.
The bomber struck after troops backed by tanks attacked an al Qaeda stronghold following the collapse of talks to free three Western hostages, local officials and residents said.
Tackling lawlessness in the impoverished Arabian Peninsula state, which flanks the world's biggest oil exporter Saudi Arabia, is an international priority. The United States views Yemen as a frontline in its struggle against al Qaeda.
A Finnish couple and an Austrian man, who were studying Arabic in Yemen, were snatched last month by tribesmen in the capital Sanaa. They were later sold to al Qaeda-linked members, and transferred to the southern al-Bayda province, a Yemeni official said earlier this month.
A government official said the army began its offensive in al Qaeda's al-Manaseh stronghold in al-Bayda early on Monday after the militants rejected demands to release the hostages.
Residents said they saw dozens of tanks and armoured vehicles moving at dawn towards al-Manaseh.
"A few hours later, army forces started shelling. We could hear explosions," a man who gave his name only as Abdullah said.
In an apparent reprisal for the offensive, a suicide bomber drove a car laden with explosives into an army checkpoint in Radda, a town near al-Manaseh, killing the eight soldiers, local officials said.
The bombing came after suspected militants ambushed and killed three other soldiers near Radda, according to medics. At least 20 other soldiers were wounded in both attacks.
No figures were immediately available on rebel casualties.
The kidnapping of Westerners occurs sporadically in Yemen, mostly by tribesmen seeking bargaining clout in disputes with the authorities or by al Qaeda militants.
Washington and other Western governments regard al Qaeda in the Arabian Peninsula (AQAP), which has planned attacks on international targets including airliners, as one of the most dangerous offshoots of the global militant network founded by Osama bin Laden.
There have been dozens of killings of security and military officials by suspected al Qaeda gunmen in the past year, suggesting AQAP remains resilient despite increased U.S. drone strikes and an onslaught by government forces.