Pirates dodged foreign navies and hijacked another two boats even as an international conference here yesterday explored securing one of the world's busiest shipping routes off Somalia.

On the second day of an international conference in Nairobi, a clearer global strategy was expected to emerge on how to curb pirate attacks, which are threatening world trade.

Somali pirates on Wednesday hijacked two Yemeni fishing boats near the port of Aden, maritime officials said, adding that seven fishermen had managed to escape on a smaller boat.

The latest attack brought to al least 17 the number of ships currently being held by Somali pirates, including an arms-laden Ukrainian cargo and a

Saudi-owned super-tanker carrying two million barrels of crude oil.

In his opening remarks, the UN’s top envoy for Somalia, Ahmedou Quid Abdallah, called for tough measures against pirates and their backers, and urged greater international commitment to stabilising the country.

"The growing reality of piracy is threatening the lifeline of global commerce," he said, addressing 140 delegates from 45 countries, including ministers and ambassadors.

According to the UN envoy, pirates have raked in an estimated 120 million dollars in ransom money.

With the most vijal ship ping lane to Europe under threat. Western powers have deployed more warships to the area but have so far been outwitted by the pirates and their speedboats.