At least 15 bodies were recovered by vessels from Greece's navy and the EU's Frontex agency on Monday. The Greek coastguard said one of its patrol vessels rescued two women, including one who was pregnant.

Authorities said the dead comprised two children, four women and nine men.

The UN refugee agency UNHCR, citing survivors, said 25 people had been on board the flimsy boat that sank while crossing the Aegean from Turkey.

Despite an EU-Turkey deal reached in March last year, asylum seekers still try to reach relatively prosperous Europe, although at a significantly reduced rate of 20 each day, according to the UNHCR.

On Saturday in Rome, Pope Francis described Lesbos arrival centers he visited last year as "concentration camps," and urged European nations to provide relief by receiving those "left there inside."

Hunger strike at Moria

At Moria, one of the camps on Lesbos, where the statuses of 13,800 refugees remain unresolved, 14 Kurds from Syria remain on hunger strike.

They began their protest against the slow processing of their appeals on Friday, sitting in blankets in front of the camp's asylum bureau.

In the first instance, their applications for shelter inside the EU had been rejected.

Stranded in Serbia

Similarly, nearly 8,000 asylum seekers are presently stranded in Serbia, unable to continue through toughly-enforced Hungarian and Croatian borders.

Compared to large migrant arrivals in 2015, much smaller numbers continue to steadily arrive, mainly overland through Bulgaria.