Yemen security officials say four South Korean tourists were killed in a suicide bombing in southern Yemen. They say the tourists were traveling in a convoy in the southern province of Hadramout. A South Korean diplomat at the country's embassy in Cairo also says the tourists were killed in the attack Sunday. Al-Qaida has maintained a strong presence in Yemen that is the ancestral homeland of Osama bin Laden. Yemen has cooperated with the US in fighting terrorism, but its government has struggled to confront Islamic extremists. The officials say the attack occurred near Shibam - a 16th century UNESCO World Heritage site. The officials spoke on condition of anonymity because they were not allowed to release the information.