OTTAWA - Canada's top military commander says international shipping companies need to take more responsibility for their security in light of increased pirates attacks off the east coast of Africa.

Gen. Walter Natynczyk's comments came Monday as shipping officials around the world called for a naval blockade of Somalia's coast to prevent more vessels from being seized.

The navies of the world will not be able to solve the problem by themselves, the chief of the defence staff said following a lunch-hour speech in Ottawa.

"There's a responsibility on the shipping companies in terms of where they are routing ships and the kind of protection they take, and it's an issue they have to resolve because what we have found is that the pirates are not a bunch of courageous people," Natynczyk said in answer to questions about the navy's future role in fighting high-seas piracy.

He described many of the commercial vessels and tankers passing through the Gulf Aden as "soft targets," and predicted that seafaring bandits who "see some challenge" will back off.

Four Canadian warships -- HMCS Iroquois, Calgary, Ville de Quebec and Protecteur -- have done duty in the region over the last few months, lending assistance to cargo ships and escorting vessels delivering humanitarian supplies.

Natynczyk wouldn't say how he thought shipping companies could beef up protection at sea -- or whether they should hire private security companies to arm the vessels.

"There are a lot of international law issues that have to be resolved ... but again international shipping companies have to resolve this," he said.

Shipping companies have opposed the notion of arming merchant ships, saying it would only escalate the violence and lead to bloodshed.

The brazen attacks are happening in a vast stretch of ocean and Natynczyk conceded there "needs to be an international effort" to confront the lawlessness.

Somali pirates have seized eight commercial ships in the past two weeks, including a huge supertanker belonging to the Saudis, which is loaded with $100 million worth of crude oil.

There were reports Monday that a Yemeni cargo ship was seized in the Arabian Sea after all communication was lost with the vessel.

NATO, which has been operating a task force of four warships in the region, has rejected the demand from shippers for a blockade and said its only mandate is to escort United Nations food supply convoys.

The International Association of Independent Tanker Owners said 20 tankers sail through the sea lanes in the Gulf Aden on a daily basis and many ship owners are considering a massive detour around southern Africa to avoid pirates.

Natynczyk recently returned from spending time aboard HMCS Ville de Quebec, where he presented the ship's company with a unit commendation for their actions in escorting food convoys into Mogadishu.