Updated Sunday 0.15am with rescue footage

At least eight migrants have died and 86 been rescued from a smugglers' boat after it starting sinking in the Mediterranean Sea off Libya, the Italian coast guard said.

A search is ongoing to find any possible survivors.

An aid group, not involved in the rescue, said dozens of migrants could still be missing.

The coast guard said there was no confirmation of Libyan authorities' statement that at least 25 migrants had died.

The Italian coast guard, which coordinates rescues in international waters off Libya's coast, said an aircraft on patrol for a European anti-smuggling operation had spotted the dinghy, which was in difficulty on Saturday morning.

Italian navy and coast guard vessels were involved in the rescue.

Coast guard Commander Sergio Liardo told Italian state TV RaiNews24 that "it appears the dinghy deflated" after a puncture.

When rescuers arrived in the early afternoon, some 20 migrants were still in the dinghy while others were in the water.

All eight victims were female, Mr Liardo said.

Asked about the Libyan navy's account that at least 25 migrants had perished, he said "that's not confirmed".

He said survivors told rescuers that roughly 150 migrants were aboard when the dinghy was launched from Libya's coast.

"We are looking for any eventual survivors," Mr Liardo said, adding the search would continue through the night.

Proactiva Open Arms, a Spanish humanitarian group that is one of the few NGOs which still operate their own rescue ships outside Libyan waters, said some of the migrantshad spent hours in the water before being saved.

The aid group tweeted that possibly dozens more could be missing from the boat.

Libyan Brigadier General Ayoub Qassim, a spokesman for the navy and coast guard, said the migrants' boat capsized and sank in international waters and that the Libyan navy did not have the resources to rush to their rescue.

He said the boat left Garbouli, east of the Libyan capital, Tripoli, with more than 100 people on board.

Hundreds of thousands of migrants have reached Italy in the last few years after being rescued in the central Mediterranean from traffickers' unseaworthy boats. Some 119,000 migrants arrived that way in Italy in 2017.

The International Organisation of Migration also recorded more than 3,100 deaths among migrants making the Mediterranean crossing in 2017.