Washington (CNN) The UN migration agency on Friday voted down Ken Isaacs, the Trump administration's candidate to lead the International Organization for Migration, a US official told CNN, leaving it without an American at the helm for the first time since 1951.

He was eliminated from contention after the second round of voting, a UN source told CNN.

"This was a very competitive election with three highly qualified candidates," a State Department official told CNN.

"We congratulate the winner and look forward to working with him/her. IOM is an important partner for the United States around the globe, and we are committed to working with IOM to address root causes of migration and to promote safe and legal migration," the official said.

Isaacs, who works in relief efforts for the Christian nonprofit Samaritan's Purse, was nominated in February to serve as director general of the 169-member group whose mission is to promote "humane and orderly migration" through assistance to both governments and migrants.