The number of migrants attempting the journey from Libya to Europe has gone down since last year, but the proportion of those who die on the way has risen.
One person died or went missing for every 18 people who crossed via the central Mediterranean route between January and July 2018, compared to one in 42 people in the same period in 2017, according to the UN refugee agency, UNHCR.
Aid agencies and other non-governmental organisations operating search and rescue ships face increased restrictions. On Monday the last private vessel working in the area had its registration revoked.
The EU-backed Libyan Coastguard still carries out rescues. But migrants are then held in detention centres, which rights groups have criticised as overcrowded and squalid.