Nearly 13 million Syrians are displaced after seven years of conflict in their country. No nation in recent decades has had such a large percentage of its population displaced.
In all, more than half a million asylum seekers from Syria during the 2015-16 migration surge had received permission to stay in Europe as of Dec. 31, 2016.
The renewal of diplomatic and economic ties has drawn widespread support in the U.S., but significant partisan differences on the future of the relationship between the two countries remain.