U.S. President Barack Obama nominated former U.S. envoy for North Korea policy Glyn Davies as ambassador to Thailand on Monday following a six month vacancy for the post, media outlets reported. Davies’ appointment, which has to be approved by the Senate, comes amid strained ties between the United States and Thailand, which is Washington’s oldest Asian ally.

The United States ambassador to South Korea, Mark W. Lippert, was attacked Thursday morning by a knife-wielding man who said he opposed joint American-South Korean military exercises, according to the South Korean police and journalists who were at the scene.