GENEVA - The number of migrants dying while trying to cross the Mediterranean has fallen sharply, the International Organization for Migration (IOM) said Tuesday, voicing hope the lethal trend seen since 2013 may be turning.

This year, 1,370 migrants and refugees have died trying to make the perilous crossings to Europe, on all routes -- a 24-percent drop compared to the 1,792 who had perished by this time last year, the IOM said.

So far in May, the toll stands at a total of 13 Mediterranean deaths, none of them on the eastern route between Turkey and Greece, IOM said.

By comparison, across all routes a total of 330 migrants and refugees perished trying to cross in May 2014, and 95 died during this month a year ago.

This marks "a considerable drop," IOM spokesman Joel Millman told reporters in Geneva.

He especially hailed the drop to zero deaths along the eastern route, where nearly 400 migrants and refugees perished during the first four months of the year.

That steep decline in deaths between Turkey and Greece is not surprising however, after a controversial EU-Turkey deal struck in March has all but shut down that route.

"We attribute obviously this drop in fatalities reported to the extremely sharp drop in arrivals between Turkey and Greece," Millman acknowledged.

In April, arrivals to Greece plunged nearly 90 percent, falling to 3,360 from 26,971 in March, according to IOM figures.

Under the March deal, Turkey agreed to take back migrants landing on Greek islands in exchange for incentives, including billions of euros in aid and visa-free European travel for its citizens.

The agreement is the cornerstone of the EU's plan to curb a crisis that has seen 1.25 million Syrian, Iraqi, Afghan and other migrants enter Europe since January 2015.

But Millman said the dramatically lower Mediterranean death toll this month also appeared to be connected with increased efforts by the Libyan coast guard to stop migrants from setting off on dangerous voyages, as well as more rescues at sea.

"In the last 24 hours, more than 2,700 migrants were rescued between Europe and Libya by various vessels at sea," Millman said, adding he was "encouraged by the sharp drop in fatalities."

He voiced hope that "the period of stark lethality that has been going on since 2013 may have run its course."

"Maybe we will see a safer summer than we had anticipated a few weeks ago," he said.