About 50 people have been found dead in the hold of a boat carrying migrants intercepted off the coast of Libya, the Italian coastguard says.

About 430 people had been rescued alive from the boat, a spokeswoman told Reuters news agency.

The rescue operation was carried out by a Swedish vessel, Poseidon, working with the EU’s Frontex border agency.

Thousands of migrants have died and many thousands more have been rescued after setting sail from Libya recently.

Wednesday’s rescue operation was one of 10 such missions currently taking place in the waters off Libya, the Italian coastguard spokeswoman said.

It was not immediately clear how the migrants found by the Poseidon had died.