A catalogue of failures led to the deaths at sea last year of 63 African migrants who fled Libya during the conflict that ousted Moamer Kadhafi, a European rights body said Tuesday.

The Parliamentary Assembly of the Council of Europe voted to back a report by Dutch politician Tineke Strik into the plight of 72 migrants whose boat ended up adrift in the Mediterranean.

All but nine of the 72 passengers eventually died as their food and water ran out, even though military vessels, Libyan authorities and smugglers were close at hand.

The boat finally washed ashore back in Libya two weeks after setting out.

The Council of Europe has already criticised NATO for failing to respond to the migrants, saying the alliance neglected distress calls in the military zone under its control.

But Tuesday's report broadens the blame to include search-and-rescue operations, countries with ships in the area as well as Libyan authorities and smugglers.

"Many opportunities of saving the lives of the persons on board were lost," the assembly said, demanding NATO conduct an inquiry and answer outstanding questions.

National parliaments of the states concerned should also carry out inquiries, the assembly said.

Members of the countries sharing the blame -- Malta, Spain and Italy -- strongly opposed the findings, questioning some details and the reliability of some of the sources.

Ahead of the debate, NATO Secretary General Anders Fogh Rasmussen said the "tragic accident" seemed to have resulted from an "unfortunate sequence of events."

"We prevented a massacre of the Libyan population, and at sea allied military ships participated in the rescue of about 600 people," during the uprising which overthrew Kadhafi, Rasmussen's spokesman Oana Lungescu said.

But according to the Parliamentary Assembly, which said it had spoken to credible witnesses, a helicopter and a warship saw the migrant boat without rendering aid.

The Council of Europe has said a helicopter dropped biscuits and water to the migrants at one point but never returned, and a large military ship came close contact to the boat, but ignored obvious distress signals.

"The law and practices of sea rescues have shortcomings that must be fixed," said Strik, who led the report.

A lawyer representing the survivors has said she would file a lawsuit in Paris in the name of the survivors.