ADEN/SANAA, April 8 (Reuters) - Suspected militants killed five soldiers guarding a checkpoint in southeastern Yemen on Tuesday, local officials said, and a leader of a Shi'ite Muslim party was wounded in a drive-by shooting in the capital Sanaa in which two guards died.
The incidents underscored the volatility in Yemen more than two years after long-serving President Ali Abdullah Saleh stepped down following months of protests by Yemenis demanding democratic reforms.
Saleh's successor, Abd-Rabbu Mansour Hadi, has been struggling to restore stability to the impoverished U.S.-allied country of 25 million amid multiple challenges that include a rebellion by Shi'ite Muslim rebels in the north, a secessionist movement in the south and al Qaeda-linked insurgents.
A security source said gunmen in two vehicles stormed the Buroum checkpoint on the border between Shabwa and Hadramout provinces with automatic fire and grenades, killing the five soldiers.
The attack was the third in two weeks in Hadramout. Last month suspected militants killed 20 members of Yemen's security forces in a raid on a checkpoint in Hadramout. Earlier this month, an officer and four soldiers were killed in the southeastern province.
Yemen is struggling to restore authority and one of the most active branches of al Qaeda has exploited the political turmoil.
Washington has a stake in stability in Yemen, where Islamist militants have plotted attacks against international airlines, because the country shares a long and porous border with the world's top oil exporter, Saudi Arabia.
In Sanaa, a security source and witnesses said gunmen riding in a car opened fire on Ismail al-Wazir, head of the shura council of al-Haq party - a political group associated with Shi'ite Muslim Houthi rebels based in northern Yemen.
They said Wazir, who is also a law professor at Sanaa University, was seriously wounded in the pelvis and two of his security escorts were killed.
The Houthi rebels, who have fought government forces several times under Saleh, have battled their way to the outskirts of Sanaa in clashes, before withdrawing under a government-sponsored ceasefire. (Reporting by Mohammed Mukhashaf in Aden and Mohammed Mukhashaf in Sanaa, Writing by Sami Aboudi; Editing by Yara Bayoumy and Alison Williams)