ADEN Yemen (Reuters) - At least six Yemeni soldiers were killed in two separate suicide bombings by suspected al Qaeda militants in southern Yemen on Sunday, local officials said.

The Yemeni army launched a major campaign earlier this year to flush out militants of al Qaeda in the Arabian Peninsula (AQAP) from their strongholds in southern Yemen, but militants have still been attacking state and military targets.

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 local 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.

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 by U.S.-backed military offensives.

In recent years the group has killed hundreds of people in repeated 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 2011 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.

(Reporting by Mohammed Mukhashaf; Writing by Yara Bayoumy; Editing by Raissa Kasolowsky)