Merkel's visit to the Nizip camp -- a sprawling complex where migrants are housed in tents and metal containers, about 30 miles east of the southern Turkish city of Gaziantep -- is intended to counter opponents of a contentious deal that has been criticized by human rights groups.
A tweet from European Council President Donald Tusk included a photo of Merkel and others being greeted with flowers presented by young women in white dresses: "Visiting victims of Syria war at #Nizip refugee camp in Turkey."
Under the terms of the March 18 agreement between the EU and Turkey, migrants who cross into Greece illegally after March 20 are being sent back to Turkey, CNN reported.
For every Syrian sent back to Turkey, a vetted Syrian refugee will go from Turkey to Europe to be resettled, although the maximum number is capped at 72,000 people.
In return, the EU will give Turkey billions in funding to help it provide for the migrants within its borders, and grant various political concessions.
More than 1 million people made "irregular arrivals" inside Europe's borders in 2015 alone, many of them displaced by the Syrian civil war.
By comparison, about 2.7 million Syrian refugees are registered in Turkey. A sign outside the camp visited by EU officials Saturday said, "Welcome to the world's largest refugee hosting country."