North Korean officials told the family that they would release the women to Clinton, the source said. The family then approached the former president.

The source said the White House approved the mission, which began Tuesday, North Korea time. The delicate journey comes amid increasing tensions between the U.S. and North Korea, which continues to pursue and test nuclear capabilities. Administration officials declined to comment.

The women — Laura Ling, 32, and Euna Lee, 36 — are reporters for Current TV, a San Francisco-based cable and satellite network seen in the U.S., United Kingdom and Italy.