In a dire reminder of the frequent migrant deaths en route to Europe last year, on Friday, six migrants attempting to reach Greece by boat drowned off the coast of western Turkey.

The disaster marks the worst of its kind since 21 migrants, from Syria and Pakistan, went missing in September after their boat sank off Turkey's Bodrum coast, some 120 kilometers south of Didim where Friday's incident took place.

The migrants, all Syrian nationals, were aboard a fiberglass boat that capsized due to bad weather. The Turkish Coast Guard managed to save four people from the capsized boat. Survivors said there were 13 people aboard the boat and the efforts to locate three people who went missing were ongoing.

Although Turkey has managed to decrease the number of migrants risking their lives on the rough Aegean Sea to reach nearby Greek islands after a deal with the European Union in March, many, especially Syrians fleeing the five-year-old conflict at home, still board boats in an attempt to reach Europe.

Under the deal with the EU, the favorite destination of migrants from impoverished, war-torn regions in Asia and the Middle East, Turkey agreed to take back "irregular migrants" of several nationalities from Greece in exchange for the relocation of Syrian refugees in Turkey to European Union countries.

Hundreds of migrants were brought to Turkey, though the low number is viewed as a failure of the deal according to the EU. The bloc has also pledged a visa waiver for Turks and an acceleration of Turkey's accession talks as part of the deal.

President Recep Tayyip Erdoğan recently warned that the deal may collapse if the union does not hold up its side on visa waivers, while EU officials imply scrapping the deal if Turkey continues its anti-terror crackdown, seen as problematic by the union. Figures show that, out of the 35,782 refugees intercepted by the Turkish Coast Guard so far this year, 5,506 of them were caught in January, 8,747 in February, 8,530 in March, 1,717 in April, 1,109 in May, 538 in June and 881 in July.

Interestingly, despite worsening weather conditions, the number of migrants, at least those intercepted, rose to 3,425 in September.

Since the refugee deal in March, eight refugees have died due to drowning or hypothermia. Those who went missing off the Bodrum coast have not yet been pronounced dead. Turkey's Coast Guard data shows that 69 refugees lost their lives in 2014 and 279 in 2015, mainly because of the use of unsafe vessels, such as dinghies.