Up to 250 migrants are feared drowned after two refugee boats sunk in the Mediterranean Sea, the United Nations has said.

A baby was among the bodies washed up on beaches in Libya following the latest disasters, which push the record death toll above 1,300 so far in 2017.

The country’s coastguard picked up seven migrants who said they had been on an overloaded dinghy packed with 170 people, which sank on Sunday.

Omar Koko, a coastguard commander in the western city of Zawiya, said more than 30 women and nine children were among those feared drowned.

At least 11 bodies washed up on nearby beaches and were recovered by the Red Crescent, while at least 7,500 migrants have been rescued since Thursday.

Spokesperson Mohanad Krima said: “All the bodies are of female victims and there is a girl of less than one year old.”

Survivors of a second shipwreck were rescued by the Italian coastguard, telling authorities their boat started deflating under the weight of 130 people.

In pictures: A day of refugee rescues in the Mediterranean Sea Show all 7 1 /7 In pictures: A day of refugee rescues in the Mediterranean Sea In pictures: A day of refugee rescues in the Mediterranean Sea A baby being taken on to MSF's Bourbon Argos ship from a boat carrying 130 migrants and refugees Lizzie Dearden In pictures: A day of refugee rescues in the Mediterranean Sea A refugee boat carrying 101 people being rescued by MSF's Bourbon Argos Lizzie Dearden In pictures: A day of refugee rescues in the Mediterranean Sea A refugee boat carrying 101 people being rescued by MSF's Bourbon Argos all images by Lizzie Dearden In pictures: A day of refugee rescues in the Mediterranean Sea A baby among refugees on a boat carrying 185 people off the coast of Libya Lizzie Dearden In pictures: A day of refugee rescues in the Mediterranean Sea Migrants and refugees sleeping after being rescued by MSF's Bourbon Argos ship Lizzie Dearden In pictures: A day of refugee rescues in the Mediterranean Sea A crew from MSF's Bourbon Argos ship rescuing a boat carrying 130 migrants and refugees off the coast of Libya, at sunrise Lizzie Dearden In pictures: A day of refugee rescues in the Mediterranean Sea A woman in a stretcher being lifted onto MSF's Bourbon Argos ship from a boat carrying 130 migrants and refugees off the coast of Libya Lizzie Dearden

Based on its interviews with survivors in Sicily, the UN Refugee Agency (UNHCR) estimated the number of dead at more than 80, with around 50 people rescued.

Migrant arrivals to Italy by sea are up about 30 per cent this year on 2016, when a record 181,000 people were rescued and taken ashore.

"The increasing numbers of passengers on board vessels used by traffickers, with an average of 100 to 150 people, are alarming and the main cause of shipwrecks,“ said the UN High Commissioner for Refugees Filippo Grandi.

"Risks are increased by the worsening quality of vessels and the increasing use of rubber boats instead of wooden ones.”

As well as drowning, refugees have been killed by suffocation and hypothermia in sea crossings, as well as on land by being run over, electrocuted, shot and hit by trains.

Despite a dramatic increase in deaths at sea, humanitarian organisations operating rescue ships have come under attack for allegedly aiding smugglers.

NGOs have denied all accusations of collusion as Italy's parliament carries out a fact-finding mission, while a prosecutor in Sicily has admitted he has no proof of coordination.

Boat crossings between Libya and Italy – now the deadliest sea passage in the world – have increased since the controversial EU-Turkey deal shut the comparatively shorter and safer crossing over the Aegean Sea.

Italian coastguard rescues thousands of refugees off coast of Libya

The EU is increasing cooperation with the fragile Libyan Government of National Accord (GNA) in attempts to combat people smuggling, but efforts have been hampered by the country’s ongoing civil war and grave human rights abuses.

Migrants are routinely detained, tortured, extorted or forced into labour and prostitution by gangs, who operate with impunity in the chaos following the British-backed ousting of Muammar Gaddafi in 2011.

The International Criminal Court is collecting information on the imprisonment of an estimated 20,000 migrants and their treatment, amid reports of "slave markets".

Prosecutor Fatou Bensouda told the UN Security Council her office was investigating "serious and widespread crimes allegedly committed against migrants attempting to transit through Libya".

“My office is carefully examining the feasibility of opening an investigation into migrant-related crimes in Libya should the court's jurisdictional requirements be met,” she said.

Rumours of the horrors awaiting refugees in the country have caused some migrants to divert to neighbouring Tunisia and Egypt, as well as attempts to enter Europe via Spanish enclaves bordering Morocco.

Officials said around 300 migrants attempted to cross the 6m border fence separating the enclave of Melilla from Morocco on Tuesday, with many throwing stones and missiles at police.

Melilla's interior ministry said most of the migrants have been pushed back by police but around 100 managed to enter the city amid clashes that let three migrants and a police officer in need of treatment.