After a period of relative calm, African migrants have begun arriving en masse into Italy once again, crossing through Tunisia now that Libya has become virtually impassable.

Over the weekend some 2,000 African migrants arrived on the Italian islands of Sicily and Sardinia, many of them having departed from the North African country of Tunisia.

Over the past four years, Libya has been the prime departure point for African migrants attempting to reach Italy by sea, with more than 600,000 migrants successfully making the crossing in this period. People smugglers have taken advantage of the security vacuum created by ongoing armed conflict in Libya and the lack of a single recognized government.

Since last summer, however, migrant crossings have declined sharply after Italy struck a deal with Libya, offering to train, equip, and finance the Libyan coastguard and to work together to turn back vessels and return migrants to Libya.

The deal was endorsed by European leaders and has been credited with significantly reducing the migrants flows arriving on Italy’s southern coast.

Traffickers also struck a deal with the Tripoli government and Libya’s coastguard—backed by the European Union (EU)—began patrolling the coast and intercepting migrant boats before they could reach NGO vessels that would bring them to Europe.

This spring, Libyan coastguard vessels have intercepted a number of migrant boats, returning their passengers to Africa rather than allowing them to rendezvous with NGO ships.

In early March, one vessel carrying over 100 migrants on board made it as far as the Aquarius rescue ship some 21 miles off the Libyan coast, but was stopped before it could unload its passengers for transfer to Italy.

This past weekend, however, the same Aquarius ship, used by the NGOs Doctors without Borders and SOS Mediterranean, arrived in Catania carrying 70 migrants picked up at sea.

Pro-migration forces have also struck back at Italy’s successful efforts to curb new arrivals, filing a lawsuit in the European Court of Human Rights (ECHR) alleging that Italy’s collaboration with the Libyan coastguard has subjected migrants to inhumane conditions, beatings, rape, and starvation by forcing them to return to Africa.

The lawsuit was brought by the UK-based charity Global Legal Action Network and focuses attention on a November 2017 incident in which the Libyan coastguard allegedly interfered in efforts by an NGO boat to rescue 130 migrants from a sinking vessel.

As of mid-May, 25,338 migrants have entered Europe by sea in 2018, with about 41 per cent arriving in Italy and 38 per cent to Greece, with the remainder (21 percent) arriving in Spain, according to the UN Migration Agency (IOM).

During the same period last year, more than double (54,324) the number of migrants had made the crossing and about 188,000 at this time in 2016.

Follow Thomas D. Williams on Twitter