ARI SHAPIRO, HOST:
Yemen is often described as the world's worst humanitarian crisis. A Saudi-led coalition there has been fighting Iranian-backed rebels for over five years. But today there was a glimmer of hope, as NPR's Michele Kelemen reports.
MICHELE KELEMEN, BYLINE: U.N. envoy Martin Griffiths says it's rare for him to bring good news to the Security Council on Yemen. That changed today.
MARTIN GRIFFITHS: The skies of Yemen have seen what I like to refer to as an airlift of hope.
KELEMEN: The Saudi-led coalition and the Houthi rebels are exchanging more than a thousand prisoners, following through on an agreement they made in late September. Katharina Ritz of the International Committee of the Red Cross says this is the largest and most complex prisoner exchange to date.
KATHARINA RITZ: Fighting is ongoing on the front line, and we brought them across front line. So we couldn't do this with buses. We had to do it with planes.
KELEMEN: Ritz tells NPR via Skype that those flights had to be synchronized. She was at the airport in Yemen's capital to witness it.
RITZ: There was lots of celebration. And when you watch it, people coming back home - it is quite emotional. Some of them have been detained for several years.
KELEMEN: U.N. officials are hoping to build on these prisoner releases to tackle some of the many devastating humanitarian consequences of the war. The news comes a day after Houthi rebels released two American hostages. The U.S. has been backing the Saudi-led coalition.
Michele Kelemen, NPR News, the State Department.
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