ATHENS, Greece (AP) — Two men who were among 41 people picked up over the weekend from a boat found adrift in the Mediterranean Sea described on Thursday surviving what they say was a shipwreck that might have killed up to 500 people.

Muaz Mahmud Aymo, a 25-year-old Ethiopian, and Mowlid Isman, a 28-year-old Somali, said they had been heading to Italy, leaving the Libyan port city of Tobruk on a boat with about 200 people on board. They said smugglers forced them onto a larger boat, which they said had about 300 people on board although it was dark and they couldn't see inside. The larger boat sank, they said.

Aymo said he lost his 2-year-old baby and 20-year-old wife in the sinking, while Isman said his sister and sister's baby also died.

Meanwhile, NATO Secretary-General Jens Stoltenberg said in Turkey's capital that efforts to stem the tide of migrants seeking the shores of Europe are working.

Speaking at a news conference with Turkish Foreign Affairs Minister Mevlut Cavusoglu in Ankara, Stoltenberg said the collective effort is "making a difference" and that the number of migrants crossing the Aegean Sea is "going significantly down."

Under an EU-Turkey deal signed last month, migrants arriving on Greek islands from the Turkish coast from March 20 onwards face deportation to Turkey unless they successfully apply for asylum in Greece.

Stoltenberg said Turkey, based on information that NATO provides, is "taking action to help break the business model of traffickers."

But, he warned, the fight against trafficking requires "flexibility" as smugglers can "shift their routes rapidly."

The migrant crisis, Stoltenberg added, demonstrates how urgent it is to find a solution to the Syrian conflict.

Turkey, which borders Syria, is home to 2.7 million Syrian refugees.

Suzan Fraser in Ankara, Turkey, contributed to this report.