ADEN, Yemen (Reuters) - Yemen said on Monday its security forces had foiled a planned Al-Qaeda attack in the southern province of Aden. The announcement came three days after a suicide bomber killed four soldiers and a civilian and wounded 16 people in Aden. A local newspaper said on Monday that investigators had identified the suicide bomber as a Saudi national. Yemen's state news agency Saba quoted a security source as saying six people "among some of the most dangerous elements" of Al-Qaeda were captured while trying to infiltrate into the province, which includes a port and oil refinery. The report described the intended target of the thwarted attack as "vital and economic installations," giving no further details. Months of popular protests demanding President Ali Abdullah Saleh end his 33 years in power have brought near chaos to Yemen, which is home to Al-Qaeda's potent regional wing and also faces a separatist revolt in its south and a tenuous peace with Shia rebels in its north.