LONDON - A Royal Air Force helicopter was forced to land high up a mountain in Wales on Tuesday because of a technical problem and all four people on board managed to get off safely before it caught fire, Britain's Ministry of Defence said.

The ministry said the Griffin training helicopter had made a "precautionary landing" in the Snowdonia national park and media photographs showed a dark plume of smoke rising from near the top of a mountain in the Yr Aran area.

"All four people on board exited safely. Subsequently the aircraft caught fire," the ministry said in a statement.

North Wales police said emergency services were at the scene.