Troops and aircraft attacked militant bases in southern Yemen to take back territory from insurgents linked to al-Qaeda, killing dozens, media reports said.
Accounts of the death toll varied. Abu Dhabi-based The National newspaper said 30 suspected militants were killed in the air and artillery strikes Sunday in al-Hurur just outside Jaar in Abyan province, DPA reported.
Twelve troops were killed in fighting in and around the provincial capital, Zinjibar, said the report, which cited military officials.
CNN, citing security officials, said 24 suspected militants and four soldiers were killed Sunday in the push in Abyan's Zinjibar and Jaar districts. Nine troops were wounded, they were quoted as saying.
Al-Qaeda seized the province last year amid years of fighting with the government, taking advantage of a weak central government and political turmoil in the country on the Arabian Peninsula.
President Abd Rabu Mansour Hadi, who took office in February, has vowed to fight al-Qaeda and has sent thousands of troops into the province.
On Saturday, 25 suspected militants were killed in Yemeni ground attacks in Abyan and airstrikes by US drones in the provinces of Marib and Shabwa, south-east of Sana'a, the military said.
Hadi has the backing of the United States in trying to drive out the militants. John Brennan, US President Barack Obama's counterterrorism adviser, was in Sana'a Sunday for talks with Hadi on the offensive.
The talks followed the stepping-up of US drone strikes in the country and the uncovering of a plot that the US said was by the Yemeni wing of al-Qaeda and was aimed at bringing down a US plane. News of the plot leaked out last week.
A security official told CNN that the latest offensive on Sunday captured a number of militant posts near Jaar.
"Al-Qaeda fighters are evacuating areas previously under their control due to the intensive government bombardment," the official was quoted as saying.