U.S. drone kills 5 Qaeda militants in S.Yemen: officials ADEN (Reuters) - A U.S. drone attack killed at least five suspected al Qaeda militants travelling in a car in southern Yemen's Shabwa province on Friday, local officials said. The drone set the vehicle on fire and killed all its occupants, one official said. One bystander was also killed and five were wounded, officials and residents told Reuters. A second drone hit a building used by militants but it was empty at the time, residents said. Al Qaeda has strengthened its hold on southern areas of the Arabian Peninsula country during the past year of protests against veteran ruler Ali Abdullah Saleh, who left office in February. The United States has retaliated with a campaign of drone strikes on suspected al Qaeda militants. A text message sent to journalists, purporting to come from the al Qaeda-affiliated Ansar al-Sharia (Supporters of Islamic Law) group, said two militants were "martyred" in the attack and four passersby were injured. Earlier this month, U.S. drone attacks killed at least 25 al Qaeda-linked fighters including one of their leaders, and a Yemeni air force raid killed 20, in the biggest airstrikes since the new president, Abd-Rabbu Mansour Hadi, took office. Neighboring Saudi Arabia, the world's biggest oil exporter, shares U.S. concern over the expansion of al-Qaeda's regional wing in a country next to major Red Sea oil shipping lanes. In a separate incident, suspected al Qaeda fighters shot dead two men in the southern port city of Aden on Friday, a local official said. The victims belonged to a clan that has opposed the group's militants in nearby Abyan province, he said. In a persistent dispute over fishing rights with Eritrea, Yemeni forces captured two Eritrean soldiers trying to seize a Yemeni fishing boat near the Red Sea port of Hudaida, Yemen's Interior Ministry said. Reporting by Mohammed Mukhashaf; Writing by Firouz Sedarat; editing by Tim Pearce