ADEN (Reuters) - A suspected Al-Qaeda militant blew himself up on Friday in a market in Lahj province in south Yemen, killing himself and wounding four people, a security official said.

In southeastern Hadramout province, unidentified gunmen shot dead a security officer on Friday, the official said, adding that the incident came a day after an intelligence officer was killed by gunmen in al-Mukallah, capital of the province.

He gave no further details of the incidents.

Yemen is mired with security and political problems, including threats from a powerful branch of al Qaeda, a secessionist movement in the south and Muslim Shi'ite Houthi rebels in the north.

Last week gunmen shot dead a German security guard employed by the German embassy in Yemen's capital in an attack officials said bore the hallmarks of Al-Qaeda.

The United States sees Yemen, which is next to vital shipping lanes, as a front line in its war on Al-Qaeda and has used drones there for years to attack members of the group.