(Adds military source)
By Mohammed Mukhashaf
ADEN, Yemen, Aug 31 (Reuters) - Suspected al Qaeda militants carried out two separate suicide car bombings against military locations in the south Yemen province of Shabwa on Sunday, killing several Yemeni soldiers, local officials and medical sources said.
Ansar al-Sharia, al Qaeda's local affiliate in Yemen, said on its Twitter account it had launched a "widespread campaign in Shabwa province on Sunday at noon that targeted a number of military and security locations for the Sanaa regime".
The same Twitter account has posted news from the group in the past.
The attacks were some of the most significant to be carried out by the insurgents in southern Yemen since the army launched a major campaign earlier in the year to flush out militants of al Qaeda in the Arabian Peninsula (AQAP) from their strongholds in Abyan and Shabwa provinces.
Sources gave different death tolls.
One local official said a suicide car bomber blew himself up at a military checkpoint in Gol al-Rayda district in Shabwa province, killing three soldiers.
Another official said another suicide car bomber attacked a military checkpoint in Azzan, also in Shabwa province, killing a further three soldiers. Some militants also died, he said.
Medical sources at a hospital in the port of Balhaf said they had received the corpses of 13 Yemeni soldiers and 33 others, some in critical condition, were receiving medical attention.
Hours after the attacks, a military source cited by the state news agency Saba in a text message later said that seven Yemeni soldiers had died when they confronted an attack in Shabwa and that a "number of terrorists" had been killed.
On Saturday, security forces killed five militants who tried to take over a police station in the eastern province of Hadramout, state news agency Saba said.
AQAP has become more active in Hadramout since being driven out of their power bases in the southern provinces of Shabwa and Abyan. In recent years the group has killed hundreds of people in attacks on state institutions, including army camps and state buildings across the country.
In 2011, the group took advantage of a power vacuum left by a uprising that toppled President Ali Abdullah Saleh after 33 years of rule and seized entire towns and districts in the south. They were later driven out by the army.
Yemen, an impoverished country of 25 million people, shares a long border with the world's top oil exporter Saudi Arabia and lies near some of the world's busiest shipping lanes.
The United States and its allies in the region have long worried that Yemen's political instability could allow AQAP to flourish and launch attacks overseas. (Writing by Yara Bayoumy; Editing by Stephen Powell)