(CNN) -- More violence from suspected al Qaeda militants in Yemen continued Sunday in two separate attacks. At least 13 Yemeni soldiers were killed and nine others were injured when the militants ambushed a military police headquarters in the southern Yemeni province of Hadramout, two Interior Ministry officials told CNN. The attackers "easily escaped," said Ali BaNajjar, who witnessed the ambush in Hadramout. A second attack occurred close to a checkpoint near the Yemeni presidential palace in the capital, Sanaa, according the government officials. Several militants were killed, said Mohammed al-Qayedi, a spokesman for the Interior Ministry. It's not the first time militants have targeted Sanaa security forces. On Friday, nearly 20 gunmen attacked the political security headquarters in the capital and killed four troops and injured at least four others at a checkpoint. Three attackers were killed, while the others fled unharmed.
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NEW: Suspected al Qaeda militants staged two attacks in Yemen Sunday
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NEW: One of the attacks happened at a checkpoint near the presidential palace
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Two al Qaeda suspects tried in April to abduct the U.S. Embassy workers
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One of the Americans had a gun and killed both assailants
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