( CNN ) -- Yemen says al Qaeda was behind a suicide bombing Sunday that killed four South Korean tourists , according to the Daily Yemen Post . The city of Shibam is a UNESCO World Heritage Site . The explosion Sunday evening in the city of Shibam also wounded three other tourists , said Hakim Almasmari , editor-in-chief of the English-language newspaper . Almasmari told CNN Monday that Yemen 's Interior Ministry is blaming al Qaeda . CNN could not immediately reach the Yemeni government for confirmation . The bomb was very strong and could be heard some 4 kilometers ( 2.5 miles ) away from the site , in the Al-Qubah district of Shibam , which is in Hadramot province , Almasmari said . The nationalities of the three injured people were not immediately known . The tourists were taking pictures of Shibam at sunset , Almasmari said . The old walled city is a United Nations Educational , Scientific and Cultural Organization ( UNESCO ) World Heritage Site ; sunset is the best time to take pictures of it , he said . CNN 's Caroline Faraj contributed to this report .
Yemen blamed Al Qaeda behind bombing that killed 4 tourists , according to local press . The fatalities were South Korean citizens ; nationalities of others unknown . Suicide blast occurred Sunday in city of Aden , a UNESCO World Heritage Site .