The sister of former U.S. Marine Amir Hekmati has arrived in Germany to meet him following his release from Iran as part of a prisoner swap.

Hekmati's sister, Sarah Hekmati, was upbeat as she arrived Monday at Frankfurt airport before heading toward the U.S. military's Landstuhl Regional Medical Center, where her brother was being treated along with Washington Post reporter Jason Rezaian and pastor Saeed Abedini.

"We are looking forward to meeting him, hopefully soon, and we are very excited," she said as she left the airport with her husband.

"We are waiting to see when they'll let us."

The three Americans arrived in Germany late Sunday via Switzerland. A fourth stayed in Iran.

The prisoners were exchanged for pardons or charges dropped against seven Iranians.