(FILES) This picture dated 06 October 20

AL-MUKALLA, YEMEN: (FILES) This picture dated 06 October 2002 shows a cloud of smoke billowing from French supertanker Limburg off the coast of the southeastern Yemeni port of al-Mukalla, 700km east of Aden, after an explosion ripped through the supertanker killing one and injuring 12 others. Major seaports in Asia, North America and Europe are stepping up security amid fears that ships might become terrorists' next killer carriers of choice after airplanes, truck bombs, and now trains following the 11 March 2004 blasts in Madrid that killed nearly 200 people. Experts fear that terrorists could use ships to transport operatives, equipment or weapons, raise money through legal or illicit trade, and attack larger vessels like the USS Cole, also attacked in Yemen in 2000, or the Limburg attack, which is suspected of being caused by a link to the al-Qaeda terror network. AFP PHOTO/FILES (Photo credit should read AFP/AFP via Getty Images)