U.N. Secretary-General Ban Ki-moon says he is seeking to facilitate the release of the two U.S. journalists imprisoned in North Korea.

In an interview with the Washington Times, he noted that he played a role in the release of another American journalist, Roxana Saberi, who was detained in Iran until last month.

Saying he felt a sense of responsibility, he worked behind the scenes and talked frankly to Iranian President Mahmoud Ahmadinejad about Saberi’s case when they met in Geneva in April.

The U.N. chief expressed frustration that he has not heard anything from the North regarding his efforts to free the two American reporters being held there.

Ban said he is doing all that he can to win the release of Euna Lee and Laura Ling, who were sentenced to 12 years of hard labor earlier this month. The two were arrested for trespassing at the border between North Korea and China in March.