Sudanese migrant who was trying to cross the Mediterranean to Europe has been shot and killed by Libyan coastguards after being taken back to Libya, the UN’s International Organisation for Migration (IOM) has said.

The man was part of a group of more than 100 people who were returned to shore on Thursday at the Abusitta Disembarkation point in the capital, Tripoli, but resisted being sent back to detention centres.

The IOM said that when people began running away, shots were fired. One bullet hit the man, who later died from his injuries.

The UN organisation condemned the incident and demanded that the Libyan authorities investigate and bring those responsible to justice.

"The use of live bullets against unarmed vulnerable civilians, men, women and children alike, is unacceptable under any circumstances and raises alarms over the safety of migrants and humanitarian staff,” the AFP news agency quotes the IOM’s Leonard Doyle as saying.

"Despite immediately receiving medical aid on the spot by an IOM doctor and then being transferred to a nearby clinic, he died two hours after admission,” he said.

The Libyan Coast Guard said it had picked up nearly 500 migrants from the sea in areas near Tripoli in the last six days and returned them to shore.