ROME: At least nine migrants drowned and 10 others, including four children, were missing after a tense series of rescues on Saturday in the Mediterranean that saved over 1,000 people, rescuers said.

Survivors saved by medical charity Doctors Without Borders (MSF) from a sinking rubber boat before dawn said six adults and four children were missing.

As the rescuers took 120 people to safety, there were fears that more may be missing at sea, an MSF spokeswoman said.

Nine bodies were found later in the day on another vessel, though their cause of death was unclear.

Along with the bodies of five migrants who died on Friday, they were transferred to the Norwegian Siem Pilot rescue ship, part of the Frontex European border security agency's mission in the Mediterranean. The Italian coast guard, which coordinates rescues in the area, said at least 1,000 migrants had been saved on Saturday, adding that the number may rise.

Meanwhile, British NGOs, charities and lawmakers have urged French Interior Minister Bernard Cazeneuve to ensure the safety of children in the "Jungle" Calais migrant camp during its demolition on Monday.

In a letter dated Friday, the signatories said they had "very serious worries concerning the security and well-being of unaccompanied minors and vulnerable adults".

Cazeneuve has pledged that all remaining migrants at the site, currently occupied by around 5,700 people according to official figures, would be given "dignified" shelter after the camp is cleared.

"We fear that the resources currently being deployed and the proposed responses are insufficient to ensure the effective protection of the most vulnerable, notably unaccompanied children," the letter said.

The signatories, which included Save the Children, the Refugee Council, Safe Passage UK-Citizens UK and the International Rescue Committee UK, said tensions had risen in the camp since its demolition was announced, due to a lack of clear information from the authorities about the future of its inhabitants.

They said a poorly-organised clearance would put already fragile people into an even more precarious situation.