"We're hopeful this will lead us to further success with Iran," the official told reporters in a conference call, adding that Wang appeared to be in good health and humor.
"This should be viewed as a hopeful sign by the other families," he said. "I'm hopeful that the release of Mr. Wang is a sign that the Iranians are realizing that the practice of hostage-taking diplomacy really should come to an end if Iran wants to rejoin the international community."