By Mohammed Ghobari
SANAA (Reuters) - At least 21 people were killed in Yemen on Tuesday in renewed fighting between troops and al Qaeda-linked militants in the southern city of Lawdar and a militant attack on a checkpoint in central Maarib province, officials and residents said.
Eight soldiers and five militants were killed and four soldiers wounded when al Qaeda-linked gunmen in vehicles attacked an army checkpoint in Abar, 300 km (185 miles) east of the capital Sanaa, in Maarib province, a local official said.
In Lawdar, where 57 people were killed on Monday in clashes between government forces and Ansar al-Sharia (Partisans of Islamic Law) fighters, six militants and two tribal gunmen fighting alongside the army died in renewed clashes.
A local official said on Tuesday that among the militants killed in Lawdar were two Yemeni nationals wanted by the United States for their links to al Qaeda. Their names were Ali al-Barakani Mohamar and Adel Hardaba.
Officials in Yemen have previously sometimes claimed to have killed al Qaeda militants only for them to turn up alive.
President Abd-Rabbu Mansour Hadi, who took over in February after a year of mass protests against his predecessor Ali Abdullah Saleh, is under pressure from Washington to fight the increasingly strong branch of al Qaeda in his country.
It also said in a statement that military officials had exaggerated when they said 40 militants had been killed in Monday's fighting in Lawdar - but that its own fighters had killed 50 soldiers during the day.
Residents said fighting intensified on Tuesday with warplanes bombing two sites held by the Islamist fighters 10 km (6.2 miles) west of Lawdar, destroying at least one of the tanks the group had seized.
A Defense Ministry website said some of the militants killed on Monday were foreigners, including some Saudis.
Vehicles laden with fighters and arms left the southern city of Jaar, which militants took a year ago, for Lawdar, witnesses said, while a local official in Lawdar said more tribesmen from neighboring towns had joined the fight against the Islamists.
Ansar al-Sharia seized control of part of the southern province of Abyan during the turmoil that led to Hadi replacing Saleh as president. A split in the army during that period threatened to start a civil war.
Saudi Arabia and the United States backed the transfer of power to Hadi in the hope that it would help prevent the country sliding into chaos, which might have enabled al Qaeda to establish a foothold near key oil shipping routes.
Conflict with Islamists in the south is only one of several challenges facing Hadi, who took office vowing to fight al Qaeda only to have more than 100 soldiers killed in attacks by militants in his first few days in power.
Yemen's main airport in Sanaa was paralyzed for a day on Saturday when officers and tribesmen loyal to Saleh forced it to close in protest at the sacking of the air force commander, a half-brother of Saleh. A government official said they backed down only after pressure from the United States and Gulf countries, which had crafted the deal that made Hadi president.
(Additional reporting by Mohammed Mukhashaf; Writing by Mahmoud Habboush; Editing by Tim Pearce)