The European Union (EU)'s border agency has announced a 90 percent drop in the number of migrants arriving in Greece since a highly controversial deal with Turkey came into effect, while numbers arriving in Italy via a much more dangerous route have dropped slightly.
According to Frontex the number of new arrivals on the islands of Lesbos, Kos, and Chios off the Greek mainland fell to just 2,700 in April, a 90 percent decrease on March.
There were 8,370 arrivals into Italy in April, a 13 percent decrease on the month before.
The data represents the first full month since a deal was signed between the EU and Turkey aimed at stymieing the flow of asylum seekers arriving in Europe, suggesting it may be achieving its aim of keeping people out, at least in the case of Greece.
Under the terms of the agreement, all migrants who arrive illegally in Greece are sent back to Turkey, while the EU takes one Syrian who has made a legitimate request for every one it sends back. It has been much criticized for resting on the assumption that Turkey is a safe country for migrants, when there have been numerous reports of abuses, and people being forcibly returned to war zones.
A Human Rights Watch (HRW) report on the first returns of asylum seekers from Greece to Turkey found the process was "riddled with abuses." Turkey has also "openly flouted the principle of non-refoulement by blocking Syrian asylum seekers at its border," according to HRW, denying entry to up to 100,000 people fleeing fighting as of April 18 and even shooting at some of them.
More than one million migrants arrived in Europe last year with the vast majority arriving in Greece from Turkey crossing the Aegean Sea, less than three miles at its narrowest point, in flimsy rubber dinghies.
Most of those taking the so-called "Balkan Route" in the early months of 2016 were from war-torn regions in the Middle East, with Syrians and Iraqis accounting for 60 percent of the arrivals in 2016 and Afghans another 26 percent.
There has been speculation that migrants from the Middle East facing immediate ejection from Greece may now seek to take the far more dangerous sea crossing from Egypt or Libya to Italy, a gateway to Europe that has so far mainly been used by Africans.
The North African route to Europe is far more risky for a whole host of reasons. In contrast to the crossing from Turkey to Greece, which takes a few hours, boats leaving from Libya often take two to three days to reach Italian waters, while vessels leaving from Egypt can take more than two weeks.
In Libya migrants face being detained or kidnapped by a whole host of militia groups, including the Islamic State, that operate in the country. When it comes time to board the boats smugglers often force people onboard with little or no water for the journey, and the longer crossing increases the risks of a boat capsizing far away from the shore and rescue teams.
According to data from the International Organization for Migration, the crossing from North Africa to Europe claimed the lives of one in 92 of those who attempted it last year. Data for 2016 so far shows 976 out of 31,219 people attempting it have died — equivalent to 1 in every 32 passengers.
A British parliamentary report published on on Friday warned that "Operation Sophia" — an EU mission named after a migrant baby born on a boat to a Somali woman rescued off the coast of Libya — had failed to achieve its aim of disrupting smuggling rings operating out of the troubled North African country.
According to the House of Lords report the mission has been instrumental in saving more than 9,000 lives, but was hampered in its capability to catch and prevent smugglers by its inability to work in Libyan waters.
The report also noted that a policy of destroying boats after migrants were rescued had resulted in smugglers attempting to reduce their financial losses by using rubber dinghies rather wooden vessels, despite the dinghies being "even more unsafe."
Aid agencies say it is still too early to tell if Syrians and Iraqis will attempt to start using the Egypt to Italy route instead of heading to Greece.
Egyptian visa restrictions introduced for Syrians in 2013, which include a requirement for state security clearance, appear to be a major barrier to route becoming widely used for those coming from the Middle East. However, according to the UNHCR there are currently 119,665 registered Syrian refugees already in Egypt, with most arriving before the visa regime was introduced.
Follow Harriet Salem on Twitter: @HarrietSalem
Reuters contributed to this report.